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author | AlexSm <alex@ydb.tech> | 2024-01-18 11:28:56 +0100 |
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committer | GitHub <noreply@github.com> | 2024-01-18 11:28:56 +0100 |
commit | 9d0a3761b3201e0d9db879a7adf91876ebdb0564 (patch) | |
tree | 541d11ac878c18efd7ebca81e35112aa0fef995b /contrib/libs/curl/lib/bufq.h | |
parent | 404ef8886ecc9736bc58ade6da2fbd83b486a408 (diff) | |
download | ydb-9d0a3761b3201e0d9db879a7adf91876ebdb0564.tar.gz |
Library import 8 (#1074)
* Library import 8
* Add contrib/libs/cxxsupp/libcxx/include/__verbose_abort
Diffstat (limited to 'contrib/libs/curl/lib/bufq.h')
-rw-r--r-- | contrib/libs/curl/lib/bufq.h | 265 |
1 files changed, 265 insertions, 0 deletions
diff --git a/contrib/libs/curl/lib/bufq.h b/contrib/libs/curl/lib/bufq.h new file mode 100644 index 0000000000..089d61bfe4 --- /dev/null +++ b/contrib/libs/curl/lib/bufq.h @@ -0,0 +1,265 @@ +#ifndef HEADER_CURL_BUFQ_H +#define HEADER_CURL_BUFQ_H +/*************************************************************************** + * _ _ ____ _ + * Project ___| | | | _ \| | + * / __| | | | |_) | | + * | (__| |_| | _ <| |___ + * \___|\___/|_| \_\_____| + * + * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. + * + * This software is licensed as described in the file COPYING, which + * you should have received as part of this distribution. The terms + * are also available at https://curl.se/docs/copyright.html. + * + * You may opt to use, copy, modify, merge, publish, distribute and/or sell + * copies of the Software, and permit persons to whom the Software is + * furnished to do so, under the terms of the COPYING file. + * + * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY + * KIND, either express or implied. + * + * SPDX-License-Identifier: curl + * + ***************************************************************************/ +#include "curl_setup.h" + +#include <curl/curl.h> + +/** + * A chunk of bytes for reading and writing. + * The size is fixed a creation with read and write offset + * for where unread content is. + */ +struct buf_chunk { + struct buf_chunk *next; /* to keep it in a list */ + size_t dlen; /* the amount of allocated x.data[] */ + size_t r_offset; /* first unread bytes */ + size_t w_offset; /* one after last written byte */ + union { + unsigned char data[1]; /* the buffer for `dlen` bytes */ + void *dummy; /* alignment */ + } x; +}; + +/** + * A pool for providing/keeping a number of chunks of the same size + * + * The same pool can be shared by many `bufq` instances. However, a pool + * is not thread safe. All bufqs using it are supposed to operate in the + * same thread. + */ +struct bufc_pool { + struct buf_chunk *spare; /* list of available spare chunks */ + size_t chunk_size; /* the size of chunks in this pool */ + size_t spare_count; /* current number of spare chunks in list */ + size_t spare_max; /* max number of spares to keep */ +}; + +void Curl_bufcp_init(struct bufc_pool *pool, + size_t chunk_size, size_t spare_max); + +void Curl_bufcp_free(struct bufc_pool *pool); + +/** + * A queue of byte chunks for reading and writing. + * Reading is done from `head`, writing is done to `tail`. + * + * `bufq`s can be empty or full or neither. Its `len` is the number + * of bytes that can be read. For an empty bufq, `len` will be 0. + * + * By default, a bufq can hold up to `max_chunks * chunk_size` number + * of bytes. When `max_chunks` are used (in the `head` list) and the + * `tail` chunk is full, the bufq will report that it is full. + * + * On a full bufq, `len` may be less than the maximum number of bytes, + * e.g. when the head chunk is partially read. `len` may also become + * larger than the max when option `BUFQ_OPT_SOFT_LIMIT` is used. + * + * By default, writing to a full bufq will return (-1, CURLE_AGAIN). Same + * as reading from an empty bufq. + * With `BUFQ_OPT_SOFT_LIMIT` set, a bufq will allow writing becond this + * limit and use more than `max_chunks`. However it will report that it + * is full nevertheless. This is provided for situation where writes + * preferably never fail (except for memory exhaustion). + * + * By default and without a pool, a bufq will keep chunks that read + * read empty in its `spare` list. Option `BUFQ_OPT_NO_SPARES` will + * disable that and free chunks once they become empty. + * + * When providing a pool to a bufq, all chunk creation and spare handling + * will be delegated to that pool. + */ +struct bufq { + struct buf_chunk *head; /* chunk with bytes to read from */ + struct buf_chunk *tail; /* chunk to write to */ + struct buf_chunk *spare; /* list of free chunks, unless `pool` */ + struct bufc_pool *pool; /* optional pool for free chunks */ + size_t chunk_count; /* current number of chunks in `head+spare` */ + size_t max_chunks; /* max `head` chunks to use */ + size_t chunk_size; /* size of chunks to manage */ + int opts; /* options for handling queue, see below */ +}; + +/** + * Default behaviour: chunk limit is "hard", meaning attempts to write + * more bytes than can be hold in `max_chunks` is refused and will return + * -1, CURLE_AGAIN. */ +#define BUFQ_OPT_NONE (0) +/** + * Make `max_chunks` a "soft" limit. A bufq will report that it is "full" + * when `max_chunks` are used, but allows writing beyond this limit. + */ +#define BUFQ_OPT_SOFT_LIMIT (1 << 0) +/** + * Do not keep spare chunks. + */ +#define BUFQ_OPT_NO_SPARES (1 << 1) + +/** + * Initialize a buffer queue that can hold up to `max_chunks` buffers + * each of size `chunk_size`. The bufq will not allow writing of + * more bytes than can be held in `max_chunks`. + */ +void Curl_bufq_init(struct bufq *q, size_t chunk_size, size_t max_chunks); + +/** + * Initialize a buffer queue that can hold up to `max_chunks` buffers + * each of size `chunk_size` with the given options. See `BUFQ_OPT_*`. + */ +void Curl_bufq_init2(struct bufq *q, size_t chunk_size, + size_t max_chunks, int opts); + +void Curl_bufq_initp(struct bufq *q, struct bufc_pool *pool, + size_t max_chunks, int opts); + +/** + * Reset the buffer queue to be empty. Will keep any allocated buffer + * chunks around. + */ +void Curl_bufq_reset(struct bufq *q); + +/** + * Free all resources held by the buffer queue. + */ +void Curl_bufq_free(struct bufq *q); + +/** + * Return the total amount of data in the queue. + */ +size_t Curl_bufq_len(const struct bufq *q); + +/** + * Return the total amount of free space in the queue. + * The returned length is the number of bytes that can + * be expected to be written successfully to the bufq, + * providing no memory allocations fail. + */ +size_t Curl_bufq_space(const struct bufq *q); + +/** + * Returns TRUE iff there is no data in the buffer queue. + */ +bool Curl_bufq_is_empty(const struct bufq *q); + +/** + * Returns TRUE iff there is no space left in the buffer queue. + */ +bool Curl_bufq_is_full(const struct bufq *q); + +/** + * Write buf to the end of the buffer queue. The buf is copied + * and the amount of copied bytes is returned. + * A return code of -1 indicates an error, setting `err` to the + * cause. An err of CURLE_AGAIN is returned if the buffer queue is full. + */ +ssize_t Curl_bufq_write(struct bufq *q, + const unsigned char *buf, size_t len, + CURLcode *err); + +/** + * Read buf from the start of the buffer queue. The buf is copied + * and the amount of copied bytes is returned. + * A return code of -1 indicates an error, setting `err` to the + * cause. An err of CURLE_AGAIN is returned if the buffer queue is empty. + */ +ssize_t Curl_bufq_read(struct bufq *q, unsigned char *buf, size_t len, + CURLcode *err); + +/** + * Peek at the head chunk in the buffer queue. Returns a pointer to + * the chunk buf (at the current offset) and its length. Does not + * modify the buffer queue. + * Returns TRUE iff bytes are available. Sets `pbuf` to NULL and `plen` + * to 0 when no bytes are available. + * Repeated calls return the same information until the buffer queue + * is modified, see `Curl_bufq_skip()`` + */ +bool Curl_bufq_peek(struct bufq *q, + const unsigned char **pbuf, size_t *plen); + +bool Curl_bufq_peek_at(struct bufq *q, size_t offset, + const unsigned char **pbuf, size_t *plen); + +/** + * Tell the buffer queue to discard `amount` buf bytes at the head + * of the queue. Skipping more buf than is currently buffered will + * just empty the queue. + */ +void Curl_bufq_skip(struct bufq *q, size_t amount); + +typedef ssize_t Curl_bufq_writer(void *writer_ctx, + const unsigned char *buf, size_t len, + CURLcode *err); +/** + * Passes the chunks in the buffer queue to the writer and returns + * the amount of buf written. A writer may return -1 and CURLE_AGAIN + * to indicate blocking at which point the queue will stop and return + * the amount of buf passed so far. + * -1 is returned on any other errors reported by the writer. + * Note that in case of a -1 chunks may have been written and + * the buffer queue will have different length than before. + */ +ssize_t Curl_bufq_pass(struct bufq *q, Curl_bufq_writer *writer, + void *writer_ctx, CURLcode *err); + +typedef ssize_t Curl_bufq_reader(void *reader_ctx, + unsigned char *buf, size_t len, + CURLcode *err); + +/** + * Read date and append it to the end of the buffer queue until the + * reader returns blocking or the queue is full. A reader returns + * -1 and CURLE_AGAIN to indicate blocking. + * Returns the total amount of buf read (may be 0) or -1 on other + * reader errors. + * Note that in case of a -1 chunks may have been read and + * the buffer queue will have different length than before. + */ +ssize_t Curl_bufq_slurp(struct bufq *q, Curl_bufq_reader *reader, + void *reader_ctx, CURLcode *err); + +/** + * Read *once* up to `max_len` bytes and append it to the buffer. + * if `max_len` is 0, no limit is imposed besides the chunk space. + * Returns the total amount of buf read (may be 0) or -1 on other + * reader errors. + */ +ssize_t Curl_bufq_sipn(struct bufq *q, size_t max_len, + Curl_bufq_reader *reader, void *reader_ctx, + CURLcode *err); + +/** + * Write buf to the end of the buffer queue. + * Will write bufq content or passed `buf` directly using the `writer` + * callback when it sees fit. 'buf' might get passed directly + * on or is placed into the buffer, depending on `len` and current + * amount buffered, chunk size, etc. + */ +ssize_t Curl_bufq_write_pass(struct bufq *q, + const unsigned char *buf, size_t len, + Curl_bufq_writer *writer, void *writer_ctx, + CURLcode *err); + +#endif /* HEADER_CURL_BUFQ_H */ |