apr_buckets.h

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00001 /* Licensed to the Apache Software Foundation (ASF) under one or more
00002  * contributor license agreements.  See the NOTICE file distributed with
00003  * this work for additional information regarding copyright ownership.
00004  * The ASF licenses this file to You under the Apache License, Version 2.0
00005  * (the "License"); you may not use this file except in compliance with
00006  * the License.  You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 /**
00017  * @file apr_buckets.h
00018  * @brief APR-UTIL Buckets/Bucket Brigades
00019  */
00020 
00021 #ifndef APR_BUCKETS_H
00022 #define APR_BUCKETS_H
00023 
00024 #if defined(APR_BUCKET_DEBUG) && !defined(APR_RING_DEBUG)
00025 #define APR_RING_DEBUG
00026 #endif
00027 
00028 #include "apu.h"
00029 #include "apr_network_io.h"
00030 #include "apr_file_io.h"
00031 #include "apr_general.h"
00032 #include "apr_mmap.h"
00033 #include "apr_errno.h"
00034 #include "apr_ring.h"
00035 #include "apr.h"
00036 #if APR_HAVE_SYS_UIO_H
00037 #include <sys/uio.h>    /* for struct iovec */
00038 #endif
00039 #if APR_HAVE_STDARG_H
00040 #include <stdarg.h>
00041 #endif
00042 
00043 #ifdef __cplusplus
00044 extern "C" {
00045 #endif
00046 
00047 /**
00048  * @defgroup APR_Util_Bucket_Brigades Bucket Brigades
00049  * @ingroup APR_Util
00050  * @{ 
00051  */
00052 
00053 /** default bucket buffer size - 8KB minus room for memory allocator headers */
00054 #define APR_BUCKET_BUFF_SIZE 8000
00055 
00056 /** Determines how a bucket or brigade should be read */
00057 typedef enum {
00058     APR_BLOCK_READ,   /**< block until data becomes available */
00059     APR_NONBLOCK_READ /**< return immediately if no data is available */
00060 } apr_read_type_e;
00061 
00062 /**
00063  * The one-sentence buzzword-laden overview: Bucket brigades represent
00064  * a complex data stream that can be passed through a layered IO
00065  * system without unnecessary copying. A longer overview follows...
00066  *
00067  * A bucket brigade is a doubly linked list (ring) of buckets, so we
00068  * aren't limited to inserting at the front and removing at the end.
00069  * Buckets are only passed around as members of a brigade, although
00070  * singleton buckets can occur for short periods of time.
00071  *
00072  * Buckets are data stores of various types. They can refer to data in
00073  * memory, or part of a file or mmap area, or the output of a process,
00074  * etc. Buckets also have some type-dependent accessor functions:
00075  * read, split, copy, setaside, and destroy.
00076  *
00077  * read returns the address and size of the data in the bucket. If the
00078  * data isn't in memory then it is read in and the bucket changes type
00079  * so that it can refer to the new location of the data. If all the
00080  * data doesn't fit in the bucket then a new bucket is inserted into
00081  * the brigade to hold the rest of it.
00082  *
00083  * split divides the data in a bucket into two regions. After a split
00084  * the original bucket refers to the first part of the data and a new
00085  * bucket inserted into the brigade after the original bucket refers
00086  * to the second part of the data. Reference counts are maintained as
00087  * necessary.
00088  *
00089  * setaside ensures that the data in the bucket has a long enough
00090  * lifetime. Sometimes it is convenient to create a bucket referring
00091  * to data on the stack in the expectation that it will be consumed
00092  * (output to the network) before the stack is unwound. If that
00093  * expectation turns out not to be valid, the setaside function is
00094  * called to move the data somewhere safer.
00095  *
00096  * copy makes a duplicate of the bucket structure as long as it's
00097  * possible to have multiple references to a single copy of the
00098  * data itself.  Not all bucket types can be copied.
00099  *
00100  * destroy maintains the reference counts on the resources used by a
00101  * bucket and frees them if necessary.
00102  *
00103  * Note: all of the above functions have wrapper macros (apr_bucket_read(),
00104  * apr_bucket_destroy(), etc), and those macros should be used rather
00105  * than using the function pointers directly.
00106  *
00107  * To write a bucket brigade, they are first made into an iovec, so that we
00108  * don't write too little data at one time.  Currently we ignore compacting the
00109  * buckets into as few buckets as possible, but if we really want good
00110  * performance, then we need to compact the buckets before we convert to an
00111  * iovec, or possibly while we are converting to an iovec.
00112  */
00113 
00114 /*
00115  * Forward declaration of the main types.
00116  */
00117 
00118 /** @see apr_bucket_brigade */
00119 typedef struct apr_bucket_brigade apr_bucket_brigade;
00120 /** @see apr_bucket */
00121 typedef struct apr_bucket apr_bucket;
00122 /** @see apr_bucket_alloc_t */
00123 typedef struct apr_bucket_alloc_t apr_bucket_alloc_t;
00124 
00125 /** @see apr_bucket_type_t */
00126 typedef struct apr_bucket_type_t apr_bucket_type_t;
00127 
00128 /**
00129  * Basic bucket type
00130  */
00131 struct apr_bucket_type_t {
00132     /**
00133      * The name of the bucket type
00134      */
00135     const char *name;
00136     /** 
00137      * The number of functions this bucket understands.  Can not be less than
00138      * five.
00139      */
00140     int num_func;
00141     /**
00142      * Whether the bucket contains metadata (ie, information that
00143      * describes the regular contents of the brigade).  The metadata
00144      * is not returned by apr_bucket_read() and is not indicated by
00145      * the ->length of the apr_bucket itself.  In other words, an
00146      * empty bucket is safe to arbitrarily remove if and only if it
00147      * contains no metadata.  In this sense, "data" is just raw bytes
00148      * that are the "content" of the brigade and "metadata" describes
00149      * that data but is not a proper part of it.
00150      */
00151     enum {
00152         /** This bucket type represents actual data to send to the client. */
00153         APR_BUCKET_DATA = 0,
00154         /** This bucket type represents metadata. */
00155         APR_BUCKET_METADATA = 1
00156     } is_metadata;
00157     /**
00158      * Free the private data and any resources used by the bucket (if they
00159      *  aren't shared with another bucket).  This function is required to be
00160      *  implemented for all bucket types, though it might be a no-op on some
00161      *  of them (namely ones that never allocate any private data structures).
00162      * @param data The private data pointer from the bucket to be destroyed
00163      */
00164     void (*destroy)(void *data);
00165 
00166     /**
00167      * Read the data from the bucket. This is required to be implemented
00168      *  for all bucket types.
00169      * @param b The bucket to read from
00170      * @param str A place to store the data read.  Allocation should only be
00171      *            done if absolutely necessary. 
00172      * @param len The amount of data read.
00173      * @param block Should this read function block if there is more data that
00174      *              cannot be read immediately.
00175      */
00176     apr_status_t (*read)(apr_bucket *b, const char **str, apr_size_t *len, 
00177                          apr_read_type_e block);
00178     
00179     /**
00180      * Make it possible to set aside the data for at least as long as the
00181      *  given pool. Buckets containing data that could potentially die before
00182      *  this pool (e.g. the data resides on the stack, in a child pool of
00183      *  the given pool, or in a disjoint pool) must somehow copy, shift, or
00184      *  transform the data to have the proper lifetime.
00185      * @param e The bucket to convert
00186      * @remark Some bucket types contain data that will always outlive the
00187      *         bucket itself. For example no data (EOS and FLUSH), or the data
00188      *         resides in global, constant memory (IMMORTAL), or the data is on
00189      *      the heap (HEAP). For these buckets, apr_bucket_setaside_noop can
00190      *      be used.
00191      */
00192     apr_status_t (*setaside)(apr_bucket *e, apr_pool_t *pool);
00193 
00194     /**
00195      * Split one bucket in two at the specified position by duplicating
00196      *  the bucket structure (not the data) and modifying any necessary
00197      *  start/end/offset information.  If it's not possible to do this
00198      *  for the bucket type (perhaps the length of the data is indeterminate,
00199      *  as with pipe and socket buckets), then APR_ENOTIMPL is returned.
00200      * @param e The bucket to split
00201      * @param point The offset of the first byte in the new bucket
00202      */
00203     apr_status_t (*split)(apr_bucket *e, apr_size_t point);
00204 
00205     /**
00206      * Copy the bucket structure (not the data), assuming that this is
00207      *  possible for the bucket type. If it's not, APR_ENOTIMPL is returned.
00208      * @param e The bucket to copy
00209      * @param c Returns a pointer to the new bucket
00210      */
00211     apr_status_t (*copy)(apr_bucket *e, apr_bucket **c);
00212 
00213 };
00214 
00215 /**
00216  * apr_bucket structures are allocated on the malloc() heap and
00217  * their lifetime is controlled by the parent apr_bucket_brigade
00218  * structure. Buckets can move from one brigade to another e.g. by
00219  * calling APR_BRIGADE_CONCAT(). In general the data in a bucket has
00220  * the same lifetime as the bucket and is freed when the bucket is
00221  * destroyed; if the data is shared by more than one bucket (e.g.
00222  * after a split) the data is freed when the last bucket goes away.
00223  */
00224 struct apr_bucket {
00225     /** Links to the rest of the brigade */
00226     APR_RING_ENTRY(apr_bucket) link;
00227     /** The type of bucket.  */
00228     const apr_bucket_type_t *type;
00229     /** The length of the data in the bucket.  This could have been implemented
00230      *  with a function, but this is an optimization, because the most
00231      *  common thing to do will be to get the length.  If the length is unknown,
00232      *  the value of this field will be (apr_size_t)(-1).
00233      */
00234     apr_size_t length;
00235     /** The start of the data in the bucket relative to the private base
00236      *  pointer.  The vast majority of bucket types allow a fixed block of
00237      *  data to be referenced by multiple buckets, each bucket pointing to
00238      *  a different segment of the data.  That segment starts at base+start
00239      *  and ends at base+start+length.  
00240      *  If the length == (apr_size_t)(-1), then start == -1.
00241      */
00242     apr_off_t start;
00243     /** type-dependent data hangs off this pointer */
00244     void *data; 
00245     /**
00246      * Pointer to function used to free the bucket. This function should
00247      * always be defined and it should be consistent with the memory
00248      * function used to allocate the bucket. For example, if malloc() is 
00249      * used to allocate the bucket, this pointer should point to free().
00250      * @param e Pointer to the bucket being freed
00251      */
00252     void (*free)(void *e);
00253     /** The freelist from which this bucket was allocated */
00254     apr_bucket_alloc_t *list;
00255 };
00256 
00257 /** A list of buckets */
00258 struct apr_bucket_brigade {
00259     /** The pool to associate the brigade with.  The data is not allocated out
00260      *  of the pool, but a cleanup is registered with this pool.  If the 
00261      *  brigade is destroyed by some mechanism other than pool destruction,
00262      *  the destroying function is responsible for killing the cleanup.
00263      */
00264     apr_pool_t *p;
00265     /** The buckets in the brigade are on this list. */
00266     /*
00267      * The apr_bucket_list structure doesn't actually need a name tag
00268      * because it has no existence independent of struct apr_bucket_brigade;
00269      * the ring macros are designed so that you can leave the name tag
00270      * argument empty in this situation but apparently the Windows compiler
00271      * doesn't like that.
00272      */
00273     APR_RING_HEAD(apr_bucket_list, apr_bucket) list;
00274     /** The freelist from which this bucket was allocated */
00275     apr_bucket_alloc_t *bucket_alloc;
00276 };
00277 
00278 
00279 /**
00280  * Function called when a brigade should be flushed
00281  */
00282 typedef apr_status_t (*apr_brigade_flush)(apr_bucket_brigade *bb, void *ctx);
00283 
00284 /*
00285  * define APR_BUCKET_DEBUG if you want your brigades to be checked for
00286  * validity at every possible instant.  this will slow your code down
00287  * substantially but is a very useful debugging tool.
00288  */
00289 #ifdef APR_BUCKET_DEBUG
00290 
00291 #define APR_BRIGADE_CHECK_CONSISTENCY(b)                                \
00292         APR_RING_CHECK_CONSISTENCY(&(b)->list, apr_bucket, link)
00293 
00294 #define APR_BUCKET_CHECK_CONSISTENCY(e)                                 \
00295         APR_RING_CHECK_ELEM_CONSISTENCY((e), apr_bucket, link)
00296 
00297 #else
00298 /**
00299  * checks the ring pointers in a bucket brigade for consistency.  an
00300  * abort() will be triggered if any inconsistencies are found.
00301  *   note: this is a no-op unless APR_BUCKET_DEBUG is defined.
00302  * @param b The brigade
00303  */
00304 #define APR_BRIGADE_CHECK_CONSISTENCY(b)
00305 /**
00306  * checks the brigade a bucket is in for ring consistency.  an
00307  * abort() will be triggered if any inconsistencies are found.
00308  *   note: this is a no-op unless APR_BUCKET_DEBUG is defined.
00309  * @param e The bucket
00310  */
00311 #define APR_BUCKET_CHECK_CONSISTENCY(e)
00312 #endif
00313 
00314 
00315 /**
00316  * Wrappers around the RING macros to reduce the verbosity of the code
00317  * that handles bucket brigades.
00318  */
00319 /**
00320  * The magic pointer value that indicates the head of the brigade
00321  * @remark This is used to find the beginning and end of the brigade, eg:
00322  * <pre>
00323  *      while (e != APR_BRIGADE_SENTINEL(b)) {
00324  *          ...
00325  *          e = APR_BUCKET_NEXT(e);
00326  *      }
00327  * </pre>
00328  * @param  b The brigade
00329  * @return The magic pointer value
00330  */
00331 #define APR_BRIGADE_SENTINEL(b) APR_RING_SENTINEL(&(b)->list, apr_bucket, link)
00332 
00333 /**
00334  * Determine if the bucket brigade is empty
00335  * @param b The brigade to check
00336  * @return true or false
00337  */
00338 #define APR_BRIGADE_EMPTY(b)    APR_RING_EMPTY(&(b)->list, apr_bucket, link)
00339 
00340 /**
00341  * Return the first bucket in a brigade
00342  * @param b The brigade to query
00343  * @return The first bucket in the brigade
00344  */
00345 #define APR_BRIGADE_FIRST(b)    APR_RING_FIRST(&(b)->list)
00346 /**
00347  * Return the last bucket in a brigade
00348  * @param b The brigade to query
00349  * @return The last bucket in the brigade
00350  */
00351 #define APR_BRIGADE_LAST(b)     APR_RING_LAST(&(b)->list)
00352 
00353 /**
00354  * Insert a list of buckets at the front of a brigade
00355  * @param b The brigade to add to
00356  * @param e The first bucket in a list of buckets to insert
00357  */
00358 #define APR_BRIGADE_INSERT_HEAD(b, e) do {                              \
00359         apr_bucket *ap__b = (e);                                        \
00360         APR_RING_INSERT_HEAD(&(b)->list, ap__b, apr_bucket, link);      \
00361         APR_BRIGADE_CHECK_CONSISTENCY((b));                             \
00362     } while (0)
00363 
00364 /**
00365  * Insert a list of buckets at the end of a brigade
00366  * @param b The brigade to add to
00367  * @param e The first bucket in a list of buckets to insert
00368  */
00369 #define APR_BRIGADE_INSERT_TAIL(b, e) do {                              \
00370         apr_bucket *ap__b = (e);                                        \
00371         APR_RING_INSERT_TAIL(&(b)->list, ap__b, apr_bucket, link);      \
00372         APR_BRIGADE_CHECK_CONSISTENCY((b));                             \
00373     } while (0)
00374 
00375 /**
00376  * Concatenate brigade b onto the end of brigade a, leaving brigade b empty
00377  * @param a The first brigade
00378  * @param b The second brigade
00379  */
00380 #define APR_BRIGADE_CONCAT(a, b) do {                                   \
00381         APR_RING_CONCAT(&(a)->list, &(b)->list, apr_bucket, link);      \
00382         APR_BRIGADE_CHECK_CONSISTENCY((a));                             \
00383     } while (0)
00384 
00385 /**
00386  * Prepend brigade b onto the beginning of brigade a, leaving brigade b empty
00387  * @param a The first brigade
00388  * @param b The second brigade
00389  */
00390 #define APR_BRIGADE_PREPEND(a, b) do {                                  \
00391         APR_RING_PREPEND(&(a)->list, &(b)->list, apr_bucket, link);     \
00392         APR_BRIGADE_CHECK_CONSISTENCY((a));                             \
00393     } while (0)
00394 
00395 /**
00396  * Insert a list of buckets before a specified bucket
00397  * @param a The bucket to insert before
00398  * @param b The buckets to insert
00399  */
00400 #define APR_BUCKET_INSERT_BEFORE(a, b) do {                             \
00401         apr_bucket *ap__a = (a), *ap__b = (b);                          \
00402         APR_RING_INSERT_BEFORE(ap__a, ap__b, link);                     \
00403         APR_BUCKET_CHECK_CONSISTENCY(ap__a);                            \
00404     } while (0)
00405 
00406 /**
00407  * Insert a list of buckets after a specified bucket
00408  * @param a The bucket to insert after
00409  * @param b The buckets to insert
00410  */
00411 #define APR_BUCKET_INSERT_AFTER(a, b) do {                              \
00412         apr_bucket *ap__a = (a), *ap__b = (b);                          \
00413         APR_RING_INSERT_AFTER(ap__a, ap__b, link);                      \
00414         APR_BUCKET_CHECK_CONSISTENCY(ap__a);                            \
00415     } while (0)
00416 
00417 /**
00418  * Get the next bucket in the list
00419  * @param e The current bucket
00420  * @return The next bucket
00421  */
00422 #define APR_BUCKET_NEXT(e)      APR_RING_NEXT((e), link)
00423 /**
00424  * Get the previous bucket in the list
00425  * @param e The current bucket
00426  * @return The previous bucket
00427  */
00428 #define APR_BUCKET_PREV(e)      APR_RING_PREV((e), link)
00429 
00430 /**
00431  * Remove a bucket from its bucket brigade
00432  * @param e The bucket to remove
00433  */
00434 #define APR_BUCKET_REMOVE(e)    APR_RING_REMOVE((e), link)
00435 
00436 /**
00437  * Initialize a new bucket's prev/next pointers
00438  * @param e The bucket to initialize
00439  */
00440 #define APR_BUCKET_INIT(e)      APR_RING_ELEM_INIT((e), link)
00441 
00442 /**
00443  * Determine if a bucket contains metadata.  An empty bucket is
00444  * safe to arbitrarily remove if and only if this is false.
00445  * @param e The bucket to inspect
00446  * @return true or false
00447  */
00448 #define APR_BUCKET_IS_METADATA(e)    ((e)->type->is_metadata)
00449 
00450 /**
00451  * Determine if a bucket is a FLUSH bucket
00452  * @param e The bucket to inspect
00453  * @return true or false
00454  */
00455 #define APR_BUCKET_IS_FLUSH(e)       ((e)->type == &apr_bucket_type_flush)
00456 /**
00457  * Determine if a bucket is an EOS bucket
00458  * @param e The bucket to inspect
00459  * @return true or false
00460  */
00461 #define APR_BUCKET_IS_EOS(e)         ((e)->type == &apr_bucket_type_eos)
00462 /**
00463  * Determine if a bucket is a FILE bucket
00464  * @param e The bucket to inspect
00465  * @return true or false
00466  */
00467 #define APR_BUCKET_IS_FILE(e)        ((e)->type == &apr_bucket_type_file)
00468 /**
00469  * Determine if a bucket is a PIPE bucket
00470  * @param e The bucket to inspect
00471  * @return true or false
00472  */
00473 #define APR_BUCKET_IS_PIPE(e)        ((e)->type == &apr_bucket_type_pipe)
00474 /**
00475  * Determine if a bucket is a SOCKET bucket
00476  * @param e The bucket to inspect
00477  * @return true or false
00478  */
00479 #define APR_BUCKET_IS_SOCKET(e)      ((e)->type == &apr_bucket_type_socket)
00480 /**
00481  * Determine if a bucket is a HEAP bucket
00482  * @param e The bucket to inspect
00483  * @return true or false
00484  */
00485 #define APR_BUCKET_IS_HEAP(e)        ((e)->type == &apr_bucket_type_heap)
00486 /**
00487  * Determine if a bucket is a TRANSIENT bucket
00488  * @param e The bucket to inspect
00489  * @return true or false
00490  */
00491 #define APR_BUCKET_IS_TRANSIENT(e)   ((e)->type == &apr_bucket_type_transient)
00492 /**
00493  * Determine if a bucket is a IMMORTAL bucket
00494  * @param e The bucket to inspect
00495  * @return true or false
00496  */
00497 #define APR_BUCKET_IS_IMMORTAL(e)    ((e)->type == &apr_bucket_type_immortal)
00498 #if APR_HAS_MMAP
00499 /**
00500  * Determine if a bucket is a MMAP bucket
00501  * @param e The bucket to inspect
00502  * @return true or false
00503  */
00504 #define APR_BUCKET_IS_MMAP(e)        ((e)->type == &apr_bucket_type_mmap)
00505 #endif
00506 /**
00507  * Determine if a bucket is a POOL bucket
00508  * @param e The bucket to inspect
00509  * @return true or false
00510  */
00511 #define APR_BUCKET_IS_POOL(e)        ((e)->type == &apr_bucket_type_pool)
00512 
00513 /*
00514  * General-purpose reference counting for the various bucket types.
00515  *
00516  * Any bucket type that keeps track of the resources it uses (i.e.
00517  * most of them except for IMMORTAL, TRANSIENT, and EOS) needs to
00518  * attach a reference count to the resource so that it can be freed
00519  * when the last bucket that uses it goes away. Resource-sharing may
00520  * occur because of bucket splits or buckets that refer to globally
00521  * cached data. */
00522 
00523 /** @see apr_bucket_refcount */
00524 typedef struct apr_bucket_refcount apr_bucket_refcount;
00525 /**
00526  * The structure used to manage the shared resource must start with an
00527  * apr_bucket_refcount which is updated by the general-purpose refcount
00528  * code. A pointer to the bucket-type-dependent private data structure
00529  * can be cast to a pointer to an apr_bucket_refcount and vice versa.
00530  */
00531 struct apr_bucket_refcount {
00532     /** The number of references to this bucket */
00533     int          refcount;
00534 };
00535 
00536 /*  *****  Reference-counted bucket types  *****  */
00537 
00538 /** @see apr_bucket_heap */
00539 typedef struct apr_bucket_heap apr_bucket_heap;
00540 /**
00541  * A bucket referring to data allocated off the heap.
00542  */
00543 struct apr_bucket_heap {
00544     /** Number of buckets using this memory */
00545     apr_bucket_refcount  refcount;
00546     /** The start of the data actually allocated.  This should never be
00547      * modified, it is only used to free the bucket.
00548      */
00549     char    *base;
00550     /** how much memory was allocated */
00551     apr_size_t  alloc_len;
00552     /** function to use to delete the data */
00553     void (*free_func)(void *data);
00554 };
00555 
00556 /** @see apr_bucket_pool */
00557 typedef struct apr_bucket_pool apr_bucket_pool;
00558 /**
00559  * A bucket referring to data allocated from a pool
00560  */
00561 struct apr_bucket_pool {
00562     /** The pool bucket must be able to be easily morphed to a heap
00563      * bucket if the pool gets cleaned up before all references are
00564      * destroyed.  This apr_bucket_heap structure is populated automatically
00565      * when the pool gets cleaned up, and subsequent calls to pool_read()
00566      * will result in the apr_bucket in question being morphed into a
00567      * regular heap bucket.  (To avoid having to do many extra refcount
00568      * manipulations and b->data manipulations, the apr_bucket_pool
00569      * struct actually *contains* the apr_bucket_heap struct that it
00570      * will become as its first element; the two share their
00571      * apr_bucket_refcount members.)
00572      */
00573     apr_bucket_heap  heap;
00574     /** The block of data actually allocated from the pool.
00575      * Segments of this block are referenced by adjusting
00576      * the start and length of the apr_bucket accordingly.
00577      * This will be NULL after the pool gets cleaned up.
00578      */
00579     const char *base;
00580     /** The pool the data was allocated from.  When the pool
00581      * is cleaned up, this gets set to NULL as an indicator
00582      * to pool_read() that the data is now on the heap and
00583      * so it should morph the bucket into a regular heap
00584      * bucket before continuing.
00585      */
00586     apr_pool_t *pool;
00587     /** The freelist this structure was allocated from, which is
00588      * needed in the cleanup phase in order to allocate space on the heap
00589      */
00590     apr_bucket_alloc_t *list;
00591 };
00592 
00593 #if APR_HAS_MMAP
00594 /** @see apr_bucket_mmap */
00595 typedef struct apr_bucket_mmap apr_bucket_mmap;
00596 /**
00597  * A bucket referring to an mmap()ed file
00598  */
00599 struct apr_bucket_mmap {
00600     /** Number of buckets using this memory */
00601     apr_bucket_refcount  refcount;
00602     /** The mmap this sub_bucket refers to */
00603     apr_mmap_t *mmap;
00604 };
00605 #endif
00606 
00607 /** @see apr_bucket_file */
00608 typedef struct apr_bucket_file apr_bucket_file;
00609 /**
00610  * A bucket referring to an file
00611  */
00612 struct apr_bucket_file {
00613     /** Number of buckets using this memory */
00614     apr_bucket_refcount  refcount;
00615     /** The file this bucket refers to */
00616     apr_file_t *fd;
00617     /** The pool into which any needed structures should
00618      *  be created while reading from this file bucket */
00619     apr_pool_t *readpool;
00620 #if APR_HAS_MMAP
00621     /** Whether this bucket should be memory-mapped if
00622      *  a caller tries to read from it */
00623     int can_mmap;
00624 #endif /* APR_HAS_MMAP */
00625 };
00626 
00627 /** @see apr_bucket_structs */
00628 typedef union apr_bucket_structs apr_bucket_structs;
00629 /**
00630  * A union of all bucket structures so we know what
00631  * the max size is.
00632  */
00633 union apr_bucket_structs {
00634     apr_bucket      b;      /**< Bucket */
00635     apr_bucket_heap heap;   /**< Heap */
00636     apr_bucket_pool pool;   /**< Pool */
00637 #if APR_HAS_MMAP
00638     apr_bucket_mmap mmap;   /**< MMap */
00639 #endif
00640     apr_bucket_file file;   /**< File */
00641 };
00642 
00643 /**
00644  * The amount that apr_bucket_alloc() should allocate in the common case.
00645  * Note: this is twice as big as apr_bucket_structs to allow breathing
00646  * room for third-party bucket types.
00647  */
00648 #define APR_BUCKET_ALLOC_SIZE  APR_ALIGN_DEFAULT(2*sizeof(apr_bucket_structs))
00649 
00650 /*  *****  Bucket Brigade Functions  *****  */
00651 /**
00652  * Create a new bucket brigade.  The bucket brigade is originally empty.
00653  * @param p The pool to associate with the brigade.  Data is not allocated out
00654  *          of the pool, but a cleanup is registered.
00655  * @param list The bucket allocator to use
00656  * @return The empty bucket brigade
00657  */
00658 APU_DECLARE(apr_bucket_brigade *) apr_brigade_create(apr_pool_t *p,
00659                                                      apr_bucket_alloc_t *list);
00660 
00661 /**
00662  * destroy an entire bucket brigade.  This includes destroying all of the
00663  * buckets within the bucket brigade's bucket list. 
00664  * @param b The bucket brigade to destroy
00665  */
00666 APU_DECLARE(apr_status_t) apr_brigade_destroy(apr_bucket_brigade *b);
00667 
00668 /**
00669  * empty out an entire bucket brigade.  This includes destroying all of the
00670  * buckets within the bucket brigade's bucket list.  This is similar to
00671  * apr_brigade_destroy(), except that it does not deregister the brigade's
00672  * pool cleanup function.
00673  * @param data The bucket brigade to clean up
00674  * @remark Generally, you should use apr_brigade_destroy().  This function
00675  *         can be useful in situations where you have a single brigade that
00676  *         you wish to reuse many times by destroying all of the buckets in
00677  *         the brigade and putting new buckets into it later.
00678  */
00679 APU_DECLARE(apr_status_t) apr_brigade_cleanup(void *data);
00680 
00681 /**
00682  * Split a bucket brigade into two, such that the given bucket is the
00683  * first in the new bucket brigade. This function is useful when a
00684  * filter wants to pass only the initial part of a brigade to the next
00685  * filter.
00686  * @param b The brigade to split
00687  * @param e The first element of the new brigade
00688  * @return The new brigade
00689  */
00690 APU_DECLARE(apr_bucket_brigade *) apr_brigade_split(apr_bucket_brigade *b,
00691                                                     apr_bucket *e);
00692 
00693 /**
00694  * Partition a bucket brigade at a given offset (in bytes from the start of
00695  * the brigade).  This is useful whenever a filter wants to use known ranges
00696  * of bytes from the brigade; the ranges can even overlap.
00697  * @param b The brigade to partition
00698  * @param point The offset at which to partition the brigade
00699  * @param after_point Returns a pointer to the first bucket after the partition
00700  * @return APR_SUCCESS on success, APR_INCOMPLETE if the contents of the
00701  * brigade were shorter than @a point, or an error code.
00702  * @remark if APR_INCOMPLETE is returned, @a after_point will be set to
00703  * the brigade sentinel.
00704  */
00705 APU_DECLARE(apr_status_t) apr_brigade_partition(apr_bucket_brigade *b,
00706                                                 apr_off_t point,
00707                                                 apr_bucket **after_point);
00708 
00709 /**
00710  * Return the total length of the brigade.
00711  * @param bb The brigade to compute the length of
00712  * @param read_all Read unknown-length buckets to force a size
00713  * @param length Returns the length of the brigade, or -1 if the brigade has
00714  *               buckets of indeterminate length and read_all is 0.
00715  */
00716 APU_DECLARE(apr_status_t) apr_brigade_length(apr_bucket_brigade *bb,
00717                                              int read_all,
00718                                              apr_off_t *length);
00719 
00720 /**
00721  * Take a bucket brigade and store the data in a flat char*
00722  * @param bb The bucket brigade to create the char* from
00723  * @param c The char* to write into
00724  * @param len The maximum length of the char array. On return, it is the
00725  *            actual length of the char array.
00726  */
00727 APU_DECLARE(apr_status_t) apr_brigade_flatten(apr_bucket_brigade *bb,
00728                                               char *c,
00729                                               apr_size_t *len);
00730 
00731 /**
00732  * Creates a pool-allocated string representing a flat bucket brigade
00733  * @param bb The bucket brigade to create the char array from
00734  * @param c On return, the allocated char array
00735  * @param len On return, the length of the char array.
00736  * @param pool The pool to allocate the string from.
00737  */
00738 APU_DECLARE(apr_status_t) apr_brigade_pflatten(apr_bucket_brigade *bb, 
00739                                                char **c,
00740                                                apr_size_t *len,
00741                                                apr_pool_t *pool);
00742 
00743 /**
00744  * Split a brigade to represent one LF line.
00745  * @param bbOut The bucket brigade that will have the LF line appended to.
00746  * @param bbIn The input bucket brigade to search for a LF-line.
00747  * @param block The blocking mode to be used to split the line.
00748  * @param maxbytes The maximum bytes to read.  If this many bytes are seen
00749  *                 without a LF, the brigade will contain a partial line.
00750  */
00751 APU_DECLARE(apr_status_t) apr_brigade_split_line(apr_bucket_brigade *bbOut,
00752                                                  apr_bucket_brigade *bbIn,
00753                                                  apr_read_type_e block,
00754                                                  apr_off_t maxbytes);
00755 
00756 /**
00757  * create an iovec of the elements in a bucket_brigade... return number 
00758  * of elements used.  This is useful for writing to a file or to the
00759  * network efficiently.
00760  * @param b The bucket brigade to create the iovec from
00761  * @param vec The iovec to create
00762  * @param nvec The number of elements in the iovec. On return, it is the
00763  *             number of iovec elements actually filled out.
00764  */
00765 APU_DECLARE(apr_status_t) apr_brigade_to_iovec(apr_bucket_brigade *b, 
00766                                                struct iovec *vec, int *nvec);
00767 
00768 /**
00769  * This function writes a list of strings into a bucket brigade. 
00770  * @param b The bucket brigade to add to
00771  * @param flush The flush function to use if the brigade is full
00772  * @param ctx The structure to pass to the flush function
00773  * @param va A list of strings to add
00774  * @return APR_SUCCESS or error code.
00775  */
00776 APU_DECLARE(apr_status_t) apr_brigade_vputstrs(apr_bucket_brigade *b,
00777                                                apr_brigade_flush flush,
00778                                                void *ctx,
00779                                                va_list va);
00780 
00781 /**
00782  * This function writes a string into a bucket brigade.
00783  * @param b The bucket brigade to add to
00784  * @param flush The flush function to use if the brigade is full
00785  * @param ctx The structure to pass to the flush function
00786  * @param str The string to add
00787  * @param nbyte The number of bytes to write
00788  * @return APR_SUCCESS or error code
00789  */
00790 APU_DECLARE(apr_status_t) apr_brigade_write(apr_bucket_brigade *b,
00791                                             apr_brigade_flush flush, void *ctx,
00792                                             const char *str, apr_size_t nbyte);
00793 
00794 /**
00795  * This function writes multiple strings into a bucket brigade.
00796  * @param b The bucket brigade to add to
00797  * @param flush The flush function to use if the brigade is full
00798  * @param ctx The structure to pass to the flush function
00799  * @param vec The strings to add (address plus length for each)
00800  * @param nvec The number of entries in iovec
00801  * @return APR_SUCCESS or error code
00802  */
00803 APU_DECLARE(apr_status_t) apr_brigade_writev(apr_bucket_brigade *b,
00804                                              apr_brigade_flush flush,
00805                                              void *ctx,
00806                                              const struct iovec *vec,
00807                                              apr_size_t nvec);
00808 
00809 /**
00810  * This function writes a string into a bucket brigade.
00811  * @param bb The bucket brigade to add to
00812  * @param flush The flush function to use if the brigade is full
00813  * @param ctx The structure to pass to the flush function
00814  * @param str The string to add
00815  * @return APR_SUCCESS or error code
00816  */
00817 APU_DECLARE(apr_status_t) apr_brigade_puts(apr_bucket_brigade *bb,
00818                                            apr_brigade_flush flush, void *ctx,
00819                                            const char *str);
00820 
00821 /**
00822  * This function writes a character into a bucket brigade.
00823  * @param b The bucket brigade to add to
00824  * @param flush The flush function to use if the brigade is full
00825  * @param ctx The structure to pass to the flush function
00826  * @param c The character to add
00827  * @return APR_SUCCESS or error code
00828  */
00829 APU_DECLARE(apr_status_t) apr_brigade_putc(apr_bucket_brigade *b,
00830                                            apr_brigade_flush flush, void *ctx,
00831                                            const char c);
00832 
00833 /**
00834  * This function writes an unspecified number of strings into a bucket brigade.
00835  * @param b The bucket brigade to add to
00836  * @param flush The flush function to use if the brigade is full
00837  * @param ctx The structure to pass to the flush function
00838  * @param ... The strings to add
00839  * @return APR_SUCCESS or error code
00840  */
00841 APU_DECLARE_NONSTD(apr_status_t) apr_brigade_putstrs(apr_bucket_brigade *b,
00842                                                      apr_brigade_flush flush,
00843                                                      void *ctx, ...);
00844 
00845 /**
00846  * Evaluate a printf and put the resulting string at the end 
00847  * of the bucket brigade.
00848  * @param b The brigade to write to
00849  * @param flush The flush function to use if the brigade is full
00850  * @param ctx The structure to pass to the flush function
00851  * @param fmt The format of the string to write
00852  * @param ... The arguments to fill out the format
00853  * @return APR_SUCCESS or error code
00854  */
00855 APU_DECLARE_NONSTD(apr_status_t) apr_brigade_printf(apr_bucket_brigade *b, 
00856                                                     apr_brigade_flush flush,
00857                                                     void *ctx,
00858                                                     const char *fmt, ...)
00859         __attribute__((format(printf,4,5)));
00860 
00861 /**
00862  * Evaluate a printf and put the resulting string at the end 
00863  * of the bucket brigade.
00864  * @param b The brigade to write to
00865  * @param flush The flush function to use if the brigade is full
00866  * @param ctx The structure to pass to the flush function
00867  * @param fmt The format of the string to write
00868  * @param va The arguments to fill out the format
00869  * @return APR_SUCCESS or error code
00870  */
00871 APU_DECLARE(apr_status_t) apr_brigade_vprintf(apr_bucket_brigade *b, 
00872                                               apr_brigade_flush flush,
00873                                               void *ctx,
00874                                               const char *fmt, va_list va);
00875 
00876 /**
00877  * Utility function to insert a file (or a segment of a file) onto the
00878  * end of the brigade.  The file is split into multiple buckets if it
00879  * is larger than the maximum size which can be represented by a
00880  * single bucket.
00881  * @param bb the brigade to insert into
00882  * @param f the file to insert
00883  * @param start the offset of the start of the segment
00884  * @param len the length of the segment of the file to insert
00885  * @param p pool from which file buckets are allocated
00886  * @return the last bucket inserted
00887  */
00888 APU_DECLARE(apr_bucket *) apr_brigade_insert_file(apr_bucket_brigade *bb,
00889                                                   apr_file_t *f,
00890                                                   apr_off_t start,
00891                                                   apr_off_t len,
00892                                                   apr_pool_t *p);
00893 
00894 
00895 
00896 /*  *****  Bucket freelist functions *****  */
00897 /**
00898  * Create a bucket allocator.
00899  * @param p This pool's underlying apr_allocator_t is used to allocate memory
00900  *          for the bucket allocator.  When the pool is destroyed, the bucket
00901  *          allocator's cleanup routine will free all memory that has been
00902  *          allocated from it.
00903  * @remark  The reason the allocator gets its memory from the pool's
00904  *          apr_allocator_t rather than from the pool itself is because
00905  *          the bucket allocator will free large memory blocks back to the
00906  *          allocator when it's done with them, thereby preventing memory
00907  *          footprint growth that would occur if we allocated from the pool.
00908  * @warning The allocator must never be used by more than one thread at a time.
00909  */
00910 APU_DECLARE_NONSTD(apr_bucket_alloc_t *) apr_bucket_alloc_create(apr_pool_t *p);
00911 
00912 /**
00913  * Create a bucket allocator.
00914  * @param allocator This apr_allocator_t is used to allocate both the bucket
00915  *          allocator and all memory handed out by the bucket allocator.  The
00916  *          caller is responsible for destroying the bucket allocator and the
00917  *          apr_allocator_t -- no automatic cleanups will happen.
00918  * @warning The allocator must never be used by more than one thread at a time.
00919  */
00920 APU_DECLARE_NONSTD(apr_bucket_alloc_t *) apr_bucket_alloc_create_ex(apr_allocator_t *allocator);
00921 
00922 /**
00923  * Destroy a bucket allocator.
00924  * @param list The allocator to be destroyed
00925  */
00926 APU_DECLARE_NONSTD(void) apr_bucket_alloc_destroy(apr_bucket_alloc_t *list);
00927 
00928 /**
00929  * Allocate memory for use by the buckets.
00930  * @param size The amount to allocate.
00931  * @param list The allocator from which to allocate the memory.
00932  */
00933 APU_DECLARE_NONSTD(void *) apr_bucket_alloc(apr_size_t size, apr_bucket_alloc_t *list);
00934 
00935 /**
00936  * Free memory previously allocated with apr_bucket_alloc().
00937  * @param block The block of memory to be freed.
00938  */
00939 APU_DECLARE_NONSTD(void) apr_bucket_free(void *block);
00940 
00941 
00942 /*  *****  Bucket Functions  *****  */
00943 /**
00944  * Free the resources used by a bucket. If multiple buckets refer to
00945  * the same resource it is freed when the last one goes away.
00946  * @see apr_bucket_delete()
00947  * @param e The bucket to destroy
00948  */
00949 #define apr_bucket_destroy(e) do {                                      \
00950         (e)->type->destroy((e)->data);                                  \
00951         (e)->free(e);                                                   \
00952     } while (0)
00953 
00954 /**
00955  * Delete a bucket by removing it from its brigade (if any) and then
00956  * destroying it.
00957  * @remark This mainly acts as an aid in avoiding code verbosity.  It is
00958  * the preferred exact equivalent to:
00959  * <pre>
00960  *      APR_BUCKET_REMOVE(e);
00961  *      apr_bucket_destroy(e);
00962  * </pre>
00963  * @param e The bucket to delete
00964  */
00965 #define apr_bucket_delete(e) do {                                       \
00966         APR_BUCKET_REMOVE(e);                                           \
00967         apr_bucket_destroy(e);                                          \
00968     } while (0)
00969 
00970 /**
00971  * read the data from the bucket
00972  * @param e The bucket to read from
00973  * @param str The location to store the data in
00974  * @param len The amount of data read
00975  * @param block Whether the read function blocks
00976  */
00977 #define apr_bucket_read(e,str,len,block) (e)->type->read(e, str, len, block)
00978 
00979 /**
00980  * Setaside data so that stack data is not destroyed on returning from
00981  * the function
00982  * @param e The bucket to setaside
00983  * @param p The pool to setaside into
00984  */
00985 #define apr_bucket_setaside(e,p) (e)->type->setaside(e,p)
00986 
00987 /**
00988  * Split one bucket in two.
00989  * @param e The bucket to split
00990  * @param point The offset to split the bucket at
00991  */
00992 #define apr_bucket_split(e,point) (e)->type->split(e, point)
00993 
00994 /**
00995  * Copy a bucket.
00996  * @param e The bucket to copy
00997  * @param c Returns a pointer to the new bucket
00998  */
00999 #define apr_bucket_copy(e,c) (e)->type->copy(e, c)
01000 
01001 /* Bucket type handling */
01002 
01003 /**
01004  * This function simply returns APR_SUCCESS to denote that the bucket does
01005  * not require anything to happen for its setaside() function. This is
01006  * appropriate for buckets that have "immortal" data -- the data will live
01007  * at least as long as the bucket.
01008  * @param data The bucket to setaside
01009  * @param pool The pool defining the desired lifetime of the bucket data
01010  * @return APR_SUCCESS
01011  */ 
01012 APU_DECLARE_NONSTD(apr_status_t) apr_bucket_setaside_noop(apr_bucket *data,
01013                                                           apr_pool_t *pool);
01014 
01015 /**
01016  * A place holder function that signifies that the setaside function was not
01017  * implemented for this bucket
01018  * @param data The bucket to setaside
01019  * @param pool The pool defining the desired lifetime of the bucket data
01020  * @return APR_ENOTIMPL
01021  */ 
01022 APU_DECLARE_NONSTD(apr_status_t) apr_bucket_setaside_notimpl(apr_bucket *data,
01023                                                              apr_pool_t *pool);
01024 
01025 /**
01026  * A place holder function that signifies that the split function was not
01027  * implemented for this bucket
01028  * @param data The bucket to split
01029  * @param point The location to split the bucket
01030  * @return APR_ENOTIMPL
01031  */ 
01032 APU_DECLARE_NONSTD(apr_status_t) apr_bucket_split_notimpl(apr_bucket *data,
01033                                                           apr_size_t point);
01034 
01035 /**
01036  * A place holder function that signifies that the copy function was not
01037  * implemented for this bucket
01038  * @param e The bucket to copy
01039  * @param c Returns a pointer to the new bucket
01040  * @return APR_ENOTIMPL
01041  */
01042 APU_DECLARE_NONSTD(apr_status_t) apr_bucket_copy_notimpl(apr_bucket *e,
01043                                                          apr_bucket **c);
01044 
01045 /**
01046  * A place holder function that signifies that this bucket does not need
01047  * to do anything special to be destroyed.  That's only the case for buckets
01048  * that either have no data (metadata buckets) or buckets whose data pointer
01049  * points to something that's not a bucket-type-specific structure, as with
01050  * simple buckets where data points to a string and pipe buckets where data
01051  * points directly to the apr_file_t.
01052  * @param data The bucket data to destroy
01053  */ 
01054 APU_DECLARE_NONSTD(void) apr_bucket_destroy_noop(void *data);
01055 
01056 /**
01057  * There is no apr_bucket_destroy_notimpl, because destruction is required
01058  * to be implemented (it could be a noop, but only if that makes sense for
01059  * the bucket type)
01060  */
01061 
01062 /* There is no apr_bucket_read_notimpl, because it is a required function
01063  */
01064 
01065 
01066 /* All of the bucket types implemented by the core */
01067 /**
01068  * The flush bucket type.  This signifies that all data should be flushed to
01069  * the next filter.  The flush bucket should be sent with the other buckets.
01070  */
01071 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_flush;
01072 /**
01073  * The EOS bucket type.  This signifies that there will be no more data, ever.
01074  * All filters MUST send all data to the next filter when they receive a
01075  * bucket of this type
01076  */
01077 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_eos;
01078 /**
01079  * The FILE bucket type.  This bucket represents a file on disk
01080  */
01081 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_file;
01082 /**
01083  * The HEAP bucket type.  This bucket represents a data allocated from the
01084  * heap.
01085  */
01086 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_heap;
01087 #if APR_HAS_MMAP
01088 /**
01089  * The MMAP bucket type.  This bucket represents an MMAP'ed file
01090  */
01091 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_mmap;
01092 #endif
01093 /**
01094  * The POOL bucket type.  This bucket represents a data that was allocated
01095  * from a pool.  IF this bucket is still available when the pool is cleared,
01096  * the data is copied on to the heap.
01097  */
01098 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_pool;
01099 /**
01100  * The PIPE bucket type.  This bucket represents a pipe to another program.
01101  */
01102 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_pipe;
01103 /**
01104  * The IMMORTAL bucket type.  This bucket represents a segment of data that
01105  * the creator is willing to take responsibility for.  The core will do
01106  * nothing with the data in an immortal bucket
01107  */
01108 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_immortal;
01109 /**
01110  * The TRANSIENT bucket type.  This bucket represents a data allocated off
01111  * the stack.  When the setaside function is called, this data is copied on
01112  * to the heap
01113  */
01114 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_transient;
01115 /**
01116  * The SOCKET bucket type.  This bucket represents a socket to another machine
01117  */
01118 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_socket;
01119 
01120 
01121 /*  *****  Simple buckets  *****  */
01122 
01123 /**
01124  * Split a simple bucket into two at the given point.  Most non-reference
01125  * counting buckets that allow multiple references to the same block of
01126  * data (eg transient and immortal) will use this as their split function
01127  * without any additional type-specific handling.
01128  * @param b The bucket to be split
01129  * @param point The offset of the first byte in the new bucket
01130  * @return APR_EINVAL if the point is not within the bucket;
01131  *         APR_ENOMEM if allocation failed;
01132  *         or APR_SUCCESS
01133  */
01134 APU_DECLARE_NONSTD(apr_status_t) apr_bucket_simple_split(apr_bucket *b,
01135                                                          apr_size_t point);
01136 
01137 /**
01138  * Copy a simple bucket.  Most non-reference-counting buckets that allow
01139  * multiple references to the same block of data (eg transient and immortal)
01140  * will use this as their copy function without any additional type-specific
01141  * handling.
01142  * @param a The bucket to copy
01143  * @param b Returns a pointer to the new bucket
01144  * @return APR_ENOMEM if allocation failed;
01145  *         or APR_SUCCESS
01146  */
01147 APU_DECLARE_NONSTD(apr_status_t) apr_bucket_simple_copy(apr_bucket *a,
01148                                                         apr_bucket **b);
01149 
01150 
01151 /*  *****  Shared, reference-counted buckets  *****  */
01152 
01153 /**
01154  * Initialize a bucket containing reference-counted data that may be
01155  * shared. The caller must allocate the bucket if necessary and
01156  * initialize its type-dependent fields, and allocate and initialize
01157  * its own private data structure. This function should only be called
01158  * by type-specific bucket creation functions.
01159  * @param b The bucket to initialize
01160  * @param data A pointer to the private data structure
01161  *             with the reference count at the start
01162  * @param start The start of the data in the bucket
01163  *              relative to the private base pointer
01164  * @param length The length of the data in the bucket
01165  * @return The new bucket, or NULL if allocation failed
01166  */
01167 APU_DECLARE(apr_bucket *) apr_bucket_shared_make(apr_bucket *b, void *data,
01168                                                  apr_off_t start, 
01169                                                  apr_size_t length);
01170 
01171 /**
01172  * Decrement the refcount of the data in the bucket. This function
01173  * should only be called by type-specific bucket destruction functions.
01174  * @param data The private data pointer from the bucket to be destroyed
01175  * @return TRUE or FALSE; TRUE if the reference count is now
01176  *         zero, indicating that the shared resource itself can
01177  *         be destroyed by the caller.
01178  */
01179 APU_DECLARE(int) apr_bucket_shared_destroy(void *data);
01180 
01181 /**
01182  * Split a bucket into two at the given point, and adjust the refcount
01183  * to the underlying data. Most reference-counting bucket types will
01184  * be able to use this function as their split function without any
01185  * additional type-specific handling.
01186  * @param b The bucket to be split
01187  * @param point The offset of the first byte in the new bucket
01188  * @return APR_EINVAL if the point is not within the bucket;
01189  *         APR_ENOMEM if allocation failed;
01190  *         or APR_SUCCESS
01191  */
01192 APU_DECLARE_NONSTD(apr_status_t) apr_bucket_shared_split(apr_bucket *b,
01193                                                          apr_size_t point);
01194 
01195 /**
01196  * Copy a refcounted bucket, incrementing the reference count. Most
01197  * reference-counting bucket types will be able to use this function
01198  * as their copy function without any additional type-specific handling.
01199  * @param a The bucket to copy
01200  * @param b Returns a pointer to the new bucket
01201  * @return APR_ENOMEM if allocation failed;
01202            or APR_SUCCESS
01203  */
01204 APU_DECLARE_NONSTD(apr_status_t) apr_bucket_shared_copy(apr_bucket *a,
01205                                                         apr_bucket **b);
01206 
01207 
01208 /*  *****  Functions to Create Buckets of varying types  *****  */
01209 /*
01210  * Each bucket type foo has two initialization functions:
01211  * apr_bucket_foo_make which sets up some already-allocated memory as a
01212  * bucket of type foo; and apr_bucket_foo_create which allocates memory
01213  * for the bucket, calls apr_bucket_make_foo, and initializes the
01214  * bucket's list pointers. The apr_bucket_foo_make functions are used
01215  * inside the bucket code to change the type of buckets in place;
01216  * other code should call apr_bucket_foo_create. All the initialization
01217  * functions change nothing if they fail.
01218  */
01219 
01220 /**
01221  * Create an End of Stream bucket.  This indicates that there is no more data
01222  * coming from down the filter stack.  All filters should flush at this point.
01223  * @param list The freelist from which this bucket should be allocated
01224  * @return The new bucket, or NULL if allocation failed
01225  */
01226 APU_DECLARE(apr_bucket *) apr_bucket_eos_create(apr_bucket_alloc_t *list);
01227 
01228 /**
01229  * Make the bucket passed in an EOS bucket.  This indicates that there is no 
01230  * more data coming from down the filter stack.  All filters should flush at 
01231  * this point.
01232  * @param b The bucket to make into an EOS bucket
01233  * @return The new bucket, or NULL if allocation failed
01234  */
01235 APU_DECLARE(apr_bucket *) apr_bucket_eos_make(apr_bucket *b);
01236 
01237 /**
01238  * Create a flush  bucket.  This indicates that filters should flush their
01239  * data.  There is no guarantee that they will flush it, but this is the
01240  * best we can do.
01241  * @param list The freelist from which this bucket should be allocated
01242  * @return The new bucket, or NULL if allocation failed
01243  */
01244 APU_DECLARE(apr_bucket *) apr_bucket_flush_create(apr_bucket_alloc_t *list);
01245 
01246 /**
01247  * Make the bucket passed in a FLUSH  bucket.  This indicates that filters 
01248  * should flush their data.  There is no guarantee that they will flush it, 
01249  * but this is the best we can do.
01250  * @param b The bucket to make into a FLUSH bucket
01251  * @return The new bucket, or NULL if allocation failed
01252  */
01253 APU_DECLARE(apr_bucket *) apr_bucket_flush_make(apr_bucket *b);
01254 
01255 /**
01256  * Create a bucket referring to long-lived data.
01257  * @param buf The data to insert into the bucket
01258  * @param nbyte The size of the data to insert.
01259  * @param list The freelist from which this bucket should be allocated
01260  * @return The new bucket, or NULL if allocation failed
01261  */
01262 APU_DECLARE(apr_bucket *) apr_bucket_immortal_create(const char *buf, 
01263                                                      apr_size_t nbyte,
01264                                                      apr_bucket_alloc_t *list);
01265 
01266 /**
01267  * Make the bucket passed in a bucket refer to long-lived data
01268  * @param b The bucket to make into a IMMORTAL bucket
01269  * @param buf The data to insert into the bucket
01270  * @param nbyte The size of the data to insert.
01271  * @return The new bucket, or NULL if allocation failed
01272  */
01273 APU_DECLARE(apr_bucket *) apr_bucket_immortal_make(apr_bucket *b, 
01274                                                    const char *buf, 
01275                                                    apr_size_t nbyte);
01276 
01277 /**
01278  * Create a bucket referring to data on the stack.
01279  * @param buf The data to insert into the bucket
01280  * @param nbyte The size of the data to insert.
01281  * @param list The freelist from which this bucket should be allocated
01282  * @return The new bucket, or NULL if allocation failed
01283  */
01284 APU_DECLARE(apr_bucket *) apr_bucket_transient_create(const char *buf, 
01285                                                       apr_size_t nbyte,
01286                                                       apr_bucket_alloc_t *list);
01287 
01288 /**
01289  * Make the bucket passed in a bucket refer to stack data
01290  * @param b The bucket to make into a TRANSIENT bucket
01291  * @param buf The data to insert into the bucket
01292  * @param nbyte The size of the data to insert.
01293  * @return The new bucket, or NULL if allocation failed
01294  */
01295 APU_DECLARE(apr_bucket *) apr_bucket_transient_make(apr_bucket *b, 
01296                                                     const char *buf,
01297                                                     apr_size_t nbyte);
01298 
01299 /**
01300  * Create a bucket referring to memory on the heap. If the caller asks
01301  * for the data to be copied, this function always allocates 4K of
01302  * memory so that more data can be added to the bucket without
01303  * requiring another allocation. Therefore not all the data may be put
01304  * into the bucket. If copying is not requested then the bucket takes
01305  * over responsibility for free()ing the memory.
01306  * @param buf The buffer to insert into the bucket
01307  * @param nbyte The size of the buffer to insert.
01308  * @param free_func Function to use to free the data; NULL indicates that the
01309  *                  bucket should make a copy of the data
01310  * @param list The freelist from which this bucket should be allocated
01311  * @return The new bucket, or NULL if allocation failed
01312  */
01313 APU_DECLARE(apr_bucket *) apr_bucket_heap_create(const char *buf, 
01314                                                  apr_size_t nbyte,
01315                                                  void (*free_func)(void *data),
01316                                                  apr_bucket_alloc_t *list);
01317 /**
01318  * Make the bucket passed in a bucket refer to heap data
01319  * @param b The bucket to make into a HEAP bucket
01320  * @param buf The buffer to insert into the bucket
01321  * @param nbyte The size of the buffer to insert.
01322  * @param free_func Function to use to free the data; NULL indicates that the
01323  *                  bucket should make a copy of the data
01324  * @return The new bucket, or NULL if allocation failed
01325  */
01326 APU_DECLARE(apr_bucket *) apr_bucket_heap_make(apr_bucket *b, const char *buf,
01327                                                apr_size_t nbyte,
01328                                                void (*free_func)(void *data));
01329 
01330 /**
01331  * Create a bucket referring to memory allocated from a pool.
01332  *
01333  * @param buf The buffer to insert into the bucket
01334  * @param length The number of bytes referred to by this bucket
01335  * @param pool The pool the memory was allocated from
01336  * @param list The freelist from which this bucket should be allocated
01337  * @return The new bucket, or NULL if allocation failed
01338  */
01339 APU_DECLARE(apr_bucket *) apr_bucket_pool_create(const char *buf, 
01340                                                  apr_size_t length,
01341                                                  apr_pool_t *pool,
01342                                                  apr_bucket_alloc_t *list);
01343 
01344 /**
01345  * Make the bucket passed in a bucket refer to pool data
01346  * @param b The bucket to make into a pool bucket
01347  * @param buf The buffer to insert into the bucket
01348  * @param length The number of bytes referred to by this bucket
01349  * @param pool The pool the memory was allocated from
01350  * @return The new bucket, or NULL if allocation failed
01351  */
01352 APU_DECLARE(apr_bucket *) apr_bucket_pool_make(apr_bucket *b, const char *buf,
01353                                                apr_size_t length, 
01354                                                apr_pool_t *pool);
01355 
01356 #if APR_HAS_MMAP
01357 /**
01358  * Create a bucket referring to mmap()ed memory.
01359  * @param mm The mmap to insert into the bucket
01360  * @param start The offset of the first byte in the mmap
01361  *              that this bucket refers to
01362  * @param length The number of bytes referred to by this bucket
01363  * @param list The freelist from which this bucket should be allocated
01364  * @return The new bucket, or NULL if allocation failed
01365  */
01366 APU_DECLARE(apr_bucket *) apr_bucket_mmap_create(apr_mmap_t *mm, 
01367                                                  apr_off_t start,
01368                                                  apr_size_t length,
01369                                                  apr_bucket_alloc_t *list);
01370 
01371 /**
01372  * Make the bucket passed in a bucket refer to an MMAP'ed file
01373  * @param b The bucket to make into a MMAP bucket
01374  * @param mm The mmap to insert into the bucket
01375  * @param start The offset of the first byte in the mmap
01376  *              that this bucket refers to
01377  * @param length The number of bytes referred to by this bucket
01378  * @return The new bucket, or NULL if allocation failed
01379  */
01380 APU_DECLARE(apr_bucket *) apr_bucket_mmap_make(apr_bucket *b, apr_mmap_t *mm,
01381                                                apr_off_t start, 
01382                                                apr_size_t length);
01383 #endif
01384 
01385 /**
01386  * Create a bucket referring to a socket.
01387  * @param thissock The socket to put in the bucket
01388  * @param list The freelist from which this bucket should be allocated
01389  * @return The new bucket, or NULL if allocation failed
01390  */
01391 APU_DECLARE(apr_bucket *) apr_bucket_socket_create(apr_socket_t *thissock,
01392                                                    apr_bucket_alloc_t *list);
01393 /**
01394  * Make the bucket passed in a bucket refer to a socket
01395  * @param b The bucket to make into a SOCKET bucket
01396  * @param thissock The socket to put in the bucket
01397  * @return The new bucket, or NULL if allocation failed
01398  */
01399 APU_DECLARE(apr_bucket *) apr_bucket_socket_make(apr_bucket *b, 
01400                                                  apr_socket_t *thissock);
01401 
01402 /**
01403  * Create a bucket referring to a pipe.
01404  * @param thispipe The pipe to put in the bucket
01405  * @param list The freelist from which this bucket should be allocated
01406  * @return The new bucket, or NULL if allocation failed
01407  */
01408 APU_DECLARE(apr_bucket *) apr_bucket_pipe_create(apr_file_t *thispipe,
01409                                                  apr_bucket_alloc_t *list);
01410 
01411 /**
01412  * Make the bucket passed in a bucket refer to a pipe
01413  * @param b The bucket to make into a PIPE bucket
01414  * @param thispipe The pipe to put in the bucket
01415  * @return The new bucket, or NULL if allocation failed
01416  */
01417 APU_DECLARE(apr_bucket *) apr_bucket_pipe_make(apr_bucket *b, 
01418                                                apr_file_t *thispipe);
01419 
01420 /**
01421  * Create a bucket referring to a file.
01422  * @param fd The file to put in the bucket
01423  * @param offset The offset where the data of interest begins in the file
01424  * @param len The amount of data in the file we are interested in
01425  * @param p The pool into which any needed structures should be created
01426  *          while reading from this file bucket
01427  * @param list The freelist from which this bucket should be allocated
01428  * @return The new bucket, or NULL if allocation failed
01429  */
01430 APU_DECLARE(apr_bucket *) apr_bucket_file_create(apr_file_t *fd,
01431                                                  apr_off_t offset,
01432                                                  apr_size_t len, 
01433                                                  apr_pool_t *p,
01434                                                  apr_bucket_alloc_t *list);
01435 
01436 /**
01437  * Make the bucket passed in a bucket refer to a file
01438  * @param b The bucket to make into a FILE bucket
01439  * @param fd The file to put in the bucket
01440  * @param offset The offset where the data of interest begins in the file
01441  * @param len The amount of data in the file we are interested in
01442  * @param p The pool into which any needed structures should be created
01443  *          while reading from this file bucket
01444  * @return The new bucket, or NULL if allocation failed
01445  */
01446 APU_DECLARE(apr_bucket *) apr_bucket_file_make(apr_bucket *b, apr_file_t *fd,
01447                                                apr_off_t offset,
01448                                                apr_size_t len, apr_pool_t *p);
01449 
01450 /**
01451  * Enable or disable memory-mapping for a FILE bucket (default is enabled)
01452  * @param b The bucket
01453  * @param enabled Whether memory-mapping should be enabled
01454  * @return APR_SUCCESS normally, or an error code if the operation fails
01455  */
01456 APU_DECLARE(apr_status_t) apr_bucket_file_enable_mmap(apr_bucket *b,
01457                                                       int enabled);
01458 
01459 /** @} */
01460 #ifdef __cplusplus
01461 }
01462 #endif
01463 
01464 #endif /* !APR_BUCKETS_H */

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