3 files changed, 129 insertions, 2 deletions

diff --git a/src/commit.c b/src/commit.c
index 710a14e9..e589dde5 100644
--- a/src/commit.c
+++ b/src/commit.c
@@ -23,10 +23,128 @@
  * Boston, MA 02110-1301, USA.
  */
 
+#include <time.h>
+
 #include "common.h"
 #include "commit.h"
+#include "revwalk.h"
+#include "git/odb.h"
 
 const git_oid *git_commit_id(git_commit *c)
 {
 	return &c->id;
 }
+
+git_commit *git_commit_lookup(git_revpool *pool, const git_oid *id)
+{
+    git_obj commit_obj;
+    git_commit *commit = NULL;
+
+    /*
+     * TODO: check if the commit is already cached in the
+     * revpool instead of loading it from the odb
+     */
+
+    if (git_odb_read(&commit_obj, pool->db, id) < 0)
+        return NULL;
+
+    if (commit_obj.type != GIT_OBJ_COMMIT)
+        goto error_cleanup;
+
+    commit = git__malloc(sizeof(git_commit));
+    memset(commit, 0x0, sizeof(git_commit));
+
+    git_oid_cpy(&commit->id, id);
+    commit->pool = pool;
+
+    if (git_commit__parse_buffer(commit, commit_obj.data, commit_obj.len) < 0)
+        goto error_cleanup;
+
+    return commit;
+
+error_cleanup:
+    git_obj_close(&commit_obj);
+    free(commit);
+
+    return NULL;
+}
+
+int git_commit__parse_time(time_t *commit_time, char *buffer, const char *buffer_end)
+{
+	if (memcmp(buffer, "author ", 7) != 0)
+		return -1;
+
+    buffer = memchr(buffer, '\n', buffer_end - buffer);
+    if (buffer == 0 || buffer >= buffer_end)
+        return -1;
+
+	if (memcmp(buffer, "committer ", 10) != 0)
+		return -1;
+
+    buffer = memchr(buffer, '\n', buffer_end - buffer);
+    if (buffer == 0 || buffer >= buffer_end)
+        return -1;
+
+	*commit_time = strtol(buffer, &buffer, 10);
+
+    return (buffer < buffer_end) ? 0 : -1;
+}
+
+int git_commit__parse_oid(git_oid *oid, char **buffer_out, const char *buffer_end, const char *header)
+{
+    size_t sha_len = GIT_OID_HEXSZ;
+    size_t header_len = strlen(header);
+
+    char *buffer = *buffer_out;
+
+    if (buffer + (header_len + sha_len + 1) > buffer_end)
+        return -1;
+
+    if (memcmp(buffer, header, header_len) != 0)
+        return -1;
+
+    if (buffer[header_len + sha_len] != '\n')
+        return -1;
+
+    if (git_oid_mkstr(oid, buffer + header_len) < 0)
+        return -1;
+
+    *buffer_out = buffer + (header_len + sha_len + 1);
+
+    return 0;
+}
+
+int git_commit__parse_buffer(git_commit *commit, void *data, size_t len)
+{
+	char *buffer = (char *)data;
+	const char *buffer_end = (char *)data + len;
+
+    git_oid oid;
+
+    if (commit->parsed)
+		return 0;
+
+    if (git_commit__parse_oid(&oid, &buffer, buffer_end, "tree ") < 0)
+        return -1;
+
+    /*
+     * TODO: load tree into commit object
+     * TODO: commit grafts!
+     */
+
+    while (git_commit__parse_oid(&oid, &buffer, buffer_end, "parent ") == 0) {
+        git_commit *parent;
+
+        if ((parent = git_commit_lookup(commit->pool, &oid)) == NULL)
+            return -1;
+
+        // TODO: push the new commit into the revpool
+    }
+
+    if (git_commit__parse_time(&commit->commit_time, buffer, buffer_end) < 0)
+        return -1;
+
+    commit->parsed = 1;
+
+	return 0;
+}
diff --git a/src/commit.h b/src/commit.h
index 05504cd3..1cdb9a4f 100644
--- a/src/commit.h
+++ b/src/commit.h
@@ -5,11 +5,20 @@
 
 #include <time.h>
 
+#define GIT_COMMIT_SEEN     (1 << 0)
+#define GIT_COMMIT_HIDE     (1 << 1)
+#define GIT_COMMIT_DELAY    (1 << 2)
+
 struct git_commit {
 	git_oid id;
 	time_t commit_time;
+    git_revpool *pool;
 	unsigned parsed:1,
 		 flags:26;
 };
 
+int git_commit__parse_oid(git_oid *oid, char **buffer_out, const char *buffer_end, const char *header);
+int git_commit__parse_buffer(git_commit *commit, void *data, size_t len);
+int git_commit__parse_time(time_t *commit_time, char *buffer, const char *buffer_end);
+
 #endif
diff --git a/src/git/commit.h b/src/git/commit.h
index 010f258a..ea59a210 100644
--- a/src/git/commit.h
+++ b/src/git/commit.h
@@ -17,7 +17,7 @@ GIT_BEGIN_DECL
 typedef struct git_commit git_commit;
 
 /**
- * Parse (or lookup) a commit from a revision pool.
+ * Lookup a commit from a revision pool, and parse it if needed.
  * @param pool the pool to use when parsing/caching the commit.
  * @param id identity of the commit to locate.  If the object is
  *        an annotated tag it will be peeled back to the commit.
@@ -25,7 +25,7 @@ typedef struct git_commit git_commit;
  *         pool's git_odb, or if the commit is present but is
  *         too malformed to be parsed successfully.
  */
-GIT_EXTERN(git_commit *) git_commit_parse(git_revpool *pool, const git_oid *id);
+GIT_EXTERN(git_commit *) git_commit_lookup(git_revpool *pool, const git_oid *id);
 
 /**
  * Get the id of a commit.