Builtin git-diff-files, git-diff-index, git-diff-stages, and git-diff-tree.

Signed-off-by: Peter Eriksen <s022018@student.dtu.dk>
Signed-off-by: Junio C Hamano <junkio@cox.net>

builtin-diff-index.c

@@ -0,0 +1,39 @@
+#include "cache.h"
+#include "diff.h"
+#include "commit.h"
+#include "revision.h"
+#include "builtin.h"
+
+static const char diff_cache_usage[] =
+"git-diff-index [-m] [--cached] "
+"[<common diff options>] <tree-ish> [<path>...]"
+COMMON_DIFF_OPTIONS_HELP;
+
+int cmd_diff_index(int argc, const char **argv, char **envp)
+{
+	struct rev_info rev;
+	int cached = 0;
+	int i;
+
+	git_config(git_diff_config);
+	init_revisions(&rev);
+	rev.abbrev = 0;
+
+	argc = setup_revisions(argc, argv, &rev, NULL);
+	for (i = 1; i < argc; i++) {
+		const char *arg = argv[i];
+			
+		if (!strcmp(arg, "--cached"))
+			cached = 1;
+		else
+			usage(diff_cache_usage);
+	}
+	/*
+	 * Make sure there is one revision (i.e. pending object),
+	 * and there is no revision filtering parameters.
+	 */
+	if (!rev.pending_objects || rev.pending_objects->next ||
+	    rev.max_count != -1 || rev.min_age != -1 || rev.max_age != -1)
+		usage(diff_cache_usage);
+	return run_diff_index(&rev, cached);
+}