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revparse.c
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revparse.c
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/*
* 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"
#include "git2/tag.h"
#include "git2/commit.h"
GIT_BEGIN_DECL
typedef enum {
REVPARSE_STATE_INIT,
/* for "^{...}" and ^... */
REVPARSE_STATE_CARET,
/* For "~..." */
REVPARSE_STATE_LINEAR,
} revparse_state;
static void set_invalid_syntax_err(const char *spec)
{
giterr_set(GITERR_INVALID, "Refspec '%s' is not valid.", spec);
}
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 int walk_ref_history(git_object **out, const char *refspec, const char *reflogspec)
{
/* TODO */
/* Empty refspec means current branch */
/* Possible syntaxes for reflogspec:
* "8" -> 8th prior value for the ref
* "-2" -> nth branch checked out before the current one (refspec must be empty)
* "yesterday", "1 month 2 weeks 3 days 4 hours 5 seconds ago", "1979-02-26 18:30:00"
* -> value of ref at given point in time
* "upstream" or "u" -> branch the ref is set to build on top of
* */
return 0;
}
static git_object* dereference_object(git_object *obj)
{
git_otype type = git_object_type(obj);
git_object *newobj = NULL;
git_tree *tree = NULL;
switch (type) {
case GIT_OBJ_COMMIT:
if (0 == git_commit_tree(&tree, (git_commit*)obj)) {
return (git_object*)tree;
}
break;
case GIT_OBJ_TAG:
if (0 == git_tag_target(&newobj, (git_tag*)obj)) {
return newobj;
}
break;
default:
case GIT_OBJ_TREE:
case GIT_OBJ_BLOB:
case GIT_OBJ_OFS_DELTA:
case GIT_OBJ_REF_DELTA:
break;
}
/* Can't dereference some types */
return NULL;
}
static int dereference_to_type(git_object **out, git_object *obj, git_otype target_type)
{
git_object *obj1 = obj, *obj2 = obj;
while (1) {
git_otype this_type = git_object_type(obj1);
if (this_type == target_type) {
*out = obj1;
return 0;
}
/* Dereference once, if possible. */
obj2 = dereference_object(obj1);
if (!obj2) {
giterr_set(GITERR_REFERENCE, "Can't dereference to type");
return GIT_ERROR;
}
if (obj1 != obj) {
git_object_free(obj1);
}
obj1 = obj2;
}
}
static git_otype parse_obj_type(const char *str)
{
if (!strcmp(str, "{commit}")) return GIT_OBJ_COMMIT;
if (!strcmp(str, "{tree}")) return GIT_OBJ_TREE;
if (!strcmp(str, "{blob}")) return GIT_OBJ_BLOB;
if (!strcmp(str, "{tag}")) return GIT_OBJ_TAG;
return GIT_OBJ_BAD;
}
static int handle_caret_syntax(git_object **out, git_object *obj, const char *movement)
{
git_commit *commit;
int n;
if (*movement == '{') {
if (movement[strlen(movement)-1] != '}') {
set_invalid_syntax_err(movement);
return GIT_ERROR;
}
/* {} -> Dereference until we reach an object that isn't a tag. */
if (strlen(movement) == 2) {
git_object *newobj = obj;
git_object *newobj2 = newobj;
while (git_object_type(newobj2) == GIT_OBJ_TAG) {
newobj2 = dereference_object(newobj);
if (newobj != obj) git_object_free(newobj);
if (!newobj2) {
giterr_set(GITERR_REFERENCE, "Couldn't find object of target type.");
return GIT_ERROR;
}
newobj = newobj2;
}
*out = newobj2;
return 0;
}
/* {/...} -> Walk all commits until we see a commit msg that matches the phrase. */
if (movement[1] == '/') {
/* TODO */
return GIT_ERROR;
}
/* {...} -> Dereference until we reach an object of a certain type. */
if (dereference_to_type(out, obj, parse_obj_type(movement)) < 0) {
return GIT_ERROR;
}
return 0;
}
/* Dereference until we reach a commit. */
if (dereference_to_type(&obj, obj, GIT_OBJ_COMMIT) < 0) {
/* Can't dereference to a commit; fail */
return GIT_ERROR;
}
/* "^" is the same as "^1" */
if (strlen(movement) == 0) {
n = 1;
} else {
git__strtol32(&n, movement, NULL, 0);
}
commit = (git_commit*)obj;
/* "^0" just returns the input */
if (n == 0) {
*out = obj;
return 0;
}
if (git_commit_parent(&commit, commit, n-1) < 0) {
return GIT_ERROR;
}
*out = (git_object*)commit;
return 0;
}
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 *cur_obj = NULL;
git_object *next_obj = NULL;
git_buf specbuffer = GIT_BUF_INIT;
git_buf stepbuffer = GIT_BUF_INIT;
int retcode = 0;
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 == '@') {
/* '@' syntax doesn't allow chaining */
git_buf_puts(&stepbuffer, spec_cur);
retcode = walk_ref_history(out, git_buf_cstr(&specbuffer), git_buf_cstr(&stepbuffer));
goto cleanup;
} else if (*spec_cur == '^') {
next_state = REVPARSE_STATE_CARET;
} else if (*spec_cur == '~') {
next_state = REVPARSE_STATE_LINEAR;
} else {
git_buf_putc(&specbuffer, *spec_cur);
}
spec_cur++;
if (current_state != next_state) {
/* Leaving INIT state, find the object specified, in case that state needs it */
retcode = revparse_lookup_object(&next_obj, repo, git_buf_cstr(&specbuffer));
if (retcode < 0) {
goto cleanup;
}
}
break;
case REVPARSE_STATE_CARET:
/* Gather characters until NULL, '~', or '^' */
if (!*spec_cur) {
retcode = handle_caret_syntax(out,
cur_obj,
git_buf_cstr(&stepbuffer));
goto cleanup;
} else if (*spec_cur == '~') {
retcode = handle_caret_syntax(&next_obj,
cur_obj,
git_buf_cstr(&stepbuffer));
git_buf_clear(&stepbuffer);
if (retcode < 0) goto cleanup;
next_state = REVPARSE_STATE_LINEAR;
} else if (*spec_cur == '^') {
retcode = handle_caret_syntax(&next_obj,
cur_obj,
git_buf_cstr(&stepbuffer));
git_buf_clear(&stepbuffer);
if (retcode < 0) goto cleanup;
next_state = REVPARSE_STATE_CARET;
} else {
git_buf_putc(&stepbuffer, *spec_cur);
}
spec_cur++;
break;
case REVPARSE_STATE_LINEAR:
if (!*spec_cur) {
} else if (*spec_cur == '~') {
} else if (*spec_cur == '^') {
} else {
git_buf_putc(&stepbuffer, *spec_cur);
}
spec_cur++;
break;
}
current_state = next_state;
if (cur_obj != next_obj) {
git_object_free(cur_obj);
cur_obj = next_obj;
}
}
cleanup:
git_buf_free(&specbuffer);
git_buf_free(&stepbuffer);
return retcode;
}
GIT_END_DECL