[PATCH] Implementations of parsing functions

This implements the parsing functions.

Signed-Off-By: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

commit.c

@@ -0,0 +1,85 @@
+#include "commit.h"
+#include "cache.h"
+#include <string.h>
+
+const char *commit_type = "commit";
+
+struct commit *lookup_commit(unsigned char *sha1)
+{
+	struct object *obj = lookup_object(sha1);
+	if (!obj) {
+		struct commit *ret = malloc(sizeof(struct commit));
+		memset(ret, 0, sizeof(struct commit));
+		created_object(sha1, &ret->object);
+		return ret;
+	}
+	if (obj->parsed && obj->type != commit_type) {
+		error("Object %s is a %s, not a commit", 
+		      sha1_to_hex(sha1), obj->type);
+		return NULL;
+	}
+	return (struct commit *) obj;
+}
+
+static unsigned long parse_commit_date(const char *buf)
+{
+	unsigned long date;
+
+	if (memcmp(buf, "author", 6))
+		return 0;
+	while (*buf++ != '\n')
+		/* nada */;
+	if (memcmp(buf, "committer", 9))
+		return 0;
+	while (*buf++ != '>')
+		/* nada */;
+	date = strtoul(buf, NULL, 10);
+	if (date == ULONG_MAX)
+		date = 0;
+	return date;
+}
+
+int parse_commit(struct commit *item)
+{
+	char type[20];
+	void * buffer, *bufptr;
+	unsigned long size;
+	unsigned char parent[20];
+	if (item->object.parsed)
+		return 0;
+	item->object.parsed = 1;
+	buffer = bufptr = read_sha1_file(item->object.sha1, type, &size);
+	if (!buffer)
+		return error("Could not read %s",
+			     sha1_to_hex(item->object.sha1));
+	if (strcmp(type, commit_type))
+		return error("Object %s not a commit",
+			     sha1_to_hex(item->object.sha1));
+	item->object.type = commit_type;
+	get_sha1_hex(bufptr + 5, parent);
+	item->tree = lookup_tree(parent);
+	add_ref(&item->object, &item->tree->object);
+	bufptr += 46; /* "tree " + "hex sha1" + "\n" */
+	while (!memcmp(bufptr, "parent ", 7) &&
+	       !get_sha1_hex(bufptr + 7, parent)) {
+		struct commit_list *new_parent = 
+			malloc(sizeof(struct commit_list));
+		new_parent->next = item->parents;
+		new_parent->item = lookup_commit(parent);
+		add_ref(&item->object, &new_parent->item->object);
+		item->parents = new_parent;
+		bufptr += 48;
+	}
+	item->date = parse_commit_date(bufptr);
+	free(buffer);
+	return 0;
+}
+
+void free_commit_list(struct commit_list *list)
+{
+	while (list) {
+		struct commit_list *temp = list;
+		list = temp->next;
+		free(temp);
+	}
+}