include/git2/odb_backend.h

   1 /*
   2  * Copyright (C) 2009-2012 the libgit2 contributors
   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_git_odb_backend_h__
   8 #define INCLUDE_git_odb_backend_h__
   9
  10 #include "common.h"
  11 #include "types.h"
  12 #include "oid.h"
  13
  14 /**
  15  * @file git2/backend.h
  16  * @brief Git custom backend functions
  17  * @defgroup git_backend Git custom backend API
  18  * @ingroup Git
  19  * @{
  20  */
  21 GIT_BEGIN_DECL
  22
  23 struct git_odb_stream;
  24
  25 /** An instance for a custom backend */
  26 struct git_odb_backend {
  27         git_odb *odb;
  28
  29         int (* read)(
  30                         void **, size_t *, git_otype *,
  31                         struct git_odb_backend *,
  32                         const git_oid *);
  33
  34         /* To find a unique object given a prefix
  35          * of its oid.
  36          * The oid given must be so that the
  37          * remaining (GIT_OID_HEXSZ - len)*4 bits
  38          * are 0s.
  39          */
  40         int (* read_prefix)(
  41                         git_oid *,
  42                         void **, size_t *, git_otype *,
  43                         struct git_odb_backend *,
  44                         const git_oid *,
  45                         size_t);
  46
  47         int (* read_header)(
  48                         size_t *, git_otype *,
  49                         struct git_odb_backend *,
  50                         const git_oid *);
  51
  52         int (* write)(
  53                         git_oid *,
  54                         struct git_odb_backend *,
  55                         const void *,
  56                         size_t,
  57                         git_otype);
  58
  59         int (* writestream)(
  60                         struct git_odb_stream **,
  61                         struct git_odb_backend *,
  62                         size_t,
  63                         git_otype);
  64
  65         int (* readstream)(
  66                         struct git_odb_stream **,
  67                         struct git_odb_backend *,
  68                         const git_oid *);
  69
  70         int (* exists)(
  71                         struct git_odb_backend *,
  72                         const git_oid *);
  73
  74         int (*foreach)(
  75                        struct git_odb_backend *,
  76                        int (*cb)(git_oid *oid, void *data),
  77                        void *data
  78                        );
  79
  80         void (* free)(struct git_odb_backend *);
  81 };
  82
  83 /** Streaming mode */
  84 enum {
  85         GIT_STREAM_RDONLY = (1 << 1),
  86         GIT_STREAM_WRONLY = (1 << 2),
  87         GIT_STREAM_RW = (GIT_STREAM_RDONLY | GIT_STREAM_WRONLY),
  88 };
  89
  90 /** A stream to read/write from a backend */
  91 struct git_odb_stream {
  92         struct git_odb_backend *backend;
  93         int mode;
  94
  95         int (*read)(struct git_odb_stream *stream, char *buffer, size_t len);
  96         int (*write)(struct git_odb_stream *stream, const char *buffer, size_t len);
  97         int (*finalize_write)(git_oid *oid_p, struct git_odb_stream *stream);
  98         void (*free)(struct git_odb_stream *stream);
  99 };
 100
 101 GIT_EXTERN(int) git_odb_backend_pack(git_odb_backend **backend_out, const char *objects_dir);
 102 GIT_EXTERN(int) git_odb_backend_loose(git_odb_backend **backend_out, const char *objects_dir, int compression_level, int do_fsync);
 103
 104 GIT_END_DECL
 105
 106 #endif