thodg/libgit2/src/revparse.c

• Show log

  Commit

• Hash : ac250c56
  Author :
  Date : 2012-04-25T16:24:22
  

  First stab at implementation of rev-parse. This version supports refspecs of these kinds: - Full & partial SHAs - Output from "git describe" - "/refs/heads/master" (full ref names) - "master" (partial ref names) - "FETCH_HEAD" (named heads)

Download

• src/revparse.c

• /*
   * Copyright (C) 2009-2012 the libgit2 contributors
   *
   * This file is part of libgit2, distributed under the GNU GPL v2 with
   * a Linking Exception. For full terms see the included COPYING file.
   */
  
  #include <assert.h>
  
  #include "common.h"
  #include "buffer.h"
  
  #include "git2/revparse.h"
  #include "git2/object.h"
  #include "git2/oid.h"
  #include "git2/refs.h"
  
  GIT_BEGIN_DECL
  
  typedef enum {
     REVPARSE_STATE_INIT,
     
     /* for parsing "@{...}" */
     REVPARSE_STATE_REF_A,
     REVPARSE_STATE_REF_B,
  
     /* for "^{...}" and ^... */
     REVPARSE_STATE_PARENTS_A,
     REVPARSE_STATE_PARENTS_B,
  
     /* For "~..." */
     REVPARSE_STATE_LIINEAR,
  
     /* For joining parents and linear, as in "master^2~3^2" */
     REVPARSE_STATE_JOIN,
  } revparse_state;
  
  static int revparse_lookup_fully_qualifed_ref(git_object **out, git_repository *repo, const char*spec)
  {
     git_reference *ref;
     git_object *obj = NULL;
  
     if (!git_reference_lookup(&ref, repo, spec)) {
        git_reference *resolved_ref;
        if (!git_reference_resolve(&resolved_ref, ref)) {
           if (!git_object_lookup(&obj, repo, git_reference_oid(resolved_ref), GIT_OBJ_ANY)) {
              *out = obj;
           }
           git_reference_free(resolved_ref);
        }
        git_reference_free(ref);
     }
     if (obj) {
        return 0;
     }
  
     return GIT_ERROR;
  }
  
  static int revparse_lookup_object(git_object **out, git_repository *repo, const char *spec)
  {
     size_t speclen = strlen(spec);
     git_object *obj = NULL;
     git_oid oid;
     git_buf refnamebuf = GIT_BUF_INIT;
     static const char* formatters[] = {
        "refs/%s",
        "refs/tags/%s",
        "refs/heads/%s",
        "refs/remotes/%s",
        "refs/remotes/%s/HEAD",
        NULL
     };
     unsigned int i;
     const char *substr;
  
     /* "git describe" output; snip everything before/including "-g" */
     substr = strstr(spec, "-g");
     if (substr) {
        spec = substr + 2;
        speclen = strlen(spec);
     }
  
     /* SHA or prefix */
     if (!git_oid_fromstrn(&oid, spec, speclen)) {
        if (!git_object_lookup_prefix(&obj, repo, &oid, speclen, GIT_OBJ_ANY)) {
           *out = obj;
           return 0;
        }
     }
  
     /* Fully-named ref */
     if (!revparse_lookup_fully_qualifed_ref(&obj, repo, spec)) {
        *out = obj;
        return 0;
     }
  
     /* Partially-named ref; match in this order: */
     for (i=0; formatters[i]; i++) {
        git_buf_clear(&refnamebuf);
        if (git_buf_printf(&refnamebuf, formatters[i], spec) < 0) {
           return GIT_ERROR;
        }
  
        if (!revparse_lookup_fully_qualifed_ref(&obj, repo, git_buf_cstr(&refnamebuf))) {
           git_buf_free(&refnamebuf);
           *out = obj;
           return 0;
        }
     }
     git_buf_free(&refnamebuf);
  
     giterr_set(GITERR_REFERENCE, "Refspec '%s' not found.", spec);
     return GIT_ERROR;
  }
  
  
  static void set_invalid_syntax_err(const char *spec)
  {
     giterr_set(GITERR_INVALID, "Refspec '%s' is not valid.", spec);
  }
  
  
  int git_revparse_single(git_object **out, git_repository *repo, const char *spec)
  {
     revparse_state current_state = REVPARSE_STATE_INIT;
     revparse_state next_state = REVPARSE_STATE_INIT;
     const char *spec_cur = spec;
     git_object *obj = NULL;
     git_buf specbuffer = GIT_BUF_INIT;
     git_buf stepbuffer = GIT_BUF_INIT;
  
     assert(out && repo && spec);
  
     while (1) {
        switch (current_state) {
        case REVPARSE_STATE_INIT:
           if (!*spec_cur) {
              /* No operators, just a name. Find it and return. */
              return revparse_lookup_object(out, repo, spec);
           } else if (*spec_cur == '@') {
              next_state = REVPARSE_STATE_REF_A;
           }
           spec_cur++;
  
           if (current_state != next_state) {
              /* Leaving INIT state, find the object specified and carry on */
              assert(!git_buf_set(&specbuffer, spec, spec_cur - spec));
              assert(!revparse_lookup_object(&obj, repo, git_buf_cstr(&specbuffer)));
           }
           break;
  
        case REVPARSE_STATE_REF_A:
           /* Found '@', look for '{', fail otherwise */
           if (*spec_cur != '{') {
              set_invalid_syntax_err(spec);
              return GIT_ERROR;
           }
           spec_cur++;
           next_state = REVPARSE_STATE_REF_B;
           break;
  
        case REVPARSE_STATE_REF_B:
           /* Found "@{", gather things until a '}' */
           break;
        }
  
        current_state = next_state;
     }
     
     return 0;
  }
  
  
  GIT_END_DECL
  

Download