src/filebuf.h

   1 /*
   2  * Copyright (C) the libgit2 contributors. All rights reserved.
   3  *
   4  * This file is part of libgit2, distributed under the GNU GPL v2 with
   5  * a Linking Exception. For full terms see the included COPYING file.
   6  */
   7 #ifndef INCLUDE_filebuf_h__
   8 #define INCLUDE_filebuf_h__
   9
  10 #include "common.h"
  11
  12 #include "fileops.h"
  13 #include "hash.h"
  14 #include <zlib.h>
  15
  16 #ifdef GIT_THREADS
  17 #       define GIT_FILEBUF_THREADS
  18 #endif
  19
  20 #define GIT_FILEBUF_HASH_CONTENTS               (1 << 0)
  21 #define GIT_FILEBUF_APPEND                              (1 << 2)
  22 #define GIT_FILEBUF_FORCE                               (1 << 3)
  23 #define GIT_FILEBUF_TEMPORARY                   (1 << 4)
  24 #define GIT_FILEBUF_DO_NOT_BUFFER               (1 << 5)
  25 #define GIT_FILEBUF_FSYNC                               (1 << 6)
  26 #define GIT_FILEBUF_DEFLATE_SHIFT               (7)
  27
  28 #define GIT_FILELOCK_EXTENSION ".lock\0"
  29 #define GIT_FILELOCK_EXTLENGTH 6
  30
  31 typedef struct git_filebuf git_filebuf;
  32 struct git_filebuf {
  33         char *path_original;
  34         char *path_lock;
  35
  36         int (*write)(git_filebuf *file, void *source, size_t len);
  37
  38         bool compute_digest;
  39         git_hash_ctx digest;
  40
  41         unsigned char *buffer;
  42         unsigned char *z_buf;
  43
  44         z_stream zs;
  45         int flush_mode;
  46
  47         size_t buf_size, buf_pos;
  48         git_file fd;
  49         bool fd_is_open;
  50         bool created_lock;
  51         bool did_rename;
  52         bool do_not_buffer;
  53         bool do_fsync;
  54         int last_error;
  55 };
  56
  57 #define GIT_FILEBUF_INIT {0}
  58
  59 /*
  60  * The git_filebuf object lifecycle is:
  61  * - Allocate git_filebuf, preferably using GIT_FILEBUF_INIT.
  62  *
  63  * - Call git_filebuf_open() to initialize the filebuf for use.
  64  *
  65  * - Make as many calls to git_filebuf_write(), git_filebuf_printf(),
  66  *   git_filebuf_reserve() as you like. The error codes for these
  67  *   functions don't need to be checked. They are stored internally
  68  *   by the file buffer.
  69  *
  70  * - While you are writing, you may call git_filebuf_hash() to get
  71  *   the hash of all you have written so far. This function will
  72  *   fail if any of the previous writes to the buffer failed.
  73  *
  74  * - To close the git_filebuf, you may call git_filebuf_commit() or
  75  *   git_filebuf_commit_at() to save the file, or
  76  *   git_filebuf_cleanup() to abandon the file.  All of these will
  77  *   free the git_filebuf object. Likewise, all of these will fail
  78  *   if any of the previous writes to the buffer failed, and set
  79  *   an error code accordingly.
  80  */
  81 int git_filebuf_write(git_filebuf *lock, const void *buff, size_t len);
  82 int git_filebuf_reserve(git_filebuf *file, void **buff, size_t len);
  83 int git_filebuf_printf(git_filebuf *file, const char *format, ...) GIT_FORMAT_PRINTF(2, 3);
  84
  85 int git_filebuf_open(git_filebuf *lock, const char *path, int flags, mode_t mode);
  86 int git_filebuf_open_withsize(git_filebuf *file, const char *path, int flags, mode_t mode, size_t size);
  87 int git_filebuf_commit(git_filebuf *lock);
  88 int git_filebuf_commit_at(git_filebuf *lock, const char *path);
  89 void git_filebuf_cleanup(git_filebuf *lock);
  90 int git_filebuf_hash(git_oid *oid, git_filebuf *file);
  91 int git_filebuf_flush(git_filebuf *file);
  92 int git_filebuf_stats(time_t *mtime, size_t *size, git_filebuf *file);
  93
  94 #endif