log-tree: separate major part of diff-tree.

This separates out the part that deals with one-commit diff-tree
(and --stdin form) into a separate log-tree module.

There are two goals with this.  The more important one is to be
able to make this part available to "git log --diff", so that we
can have a native "git whatchanged" command.  Another is to
simplify the commit log generation part simpler.

Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 24 insertions, 202 deletions

diff --git a/diff-tree.c b/diff-tree.c
index d1265d7..2a088d1 100644
--- a/diff-tree.c
+++ b/diff-tree.c
@@ -1,152 +1,16 @@
 #include "cache.h"
 #include "diff.h"
 #include "commit.h"
+#include "log-tree.h"
 
-static int show_root_diff = 0;
-static int no_commit_id = 0;
-static int verbose_header = 0;
-static int ignore_merges = 1;
-static int combine_merges = 0;
-static int dense_combined_merges = 0;
-static int read_stdin = 0;
-static int always_show_header = 0;
-
-static const char *header = NULL;
-static const char *header_prefix = "";
-static enum cmit_fmt commit_format = CMIT_FMT_RAW;
-
-static struct diff_options diff_options;
-
-static int call_diff_flush(void)
-{
-	diffcore_std(&diff_options);
-	if (diff_queue_is_empty()) {
-		int saved_fmt = diff_options.output_format;
-		diff_options.output_format = DIFF_FORMAT_NO_OUTPUT;
-		diff_flush(&diff_options);
-		diff_options.output_format = saved_fmt;
-		return 0;
-	}
-	if (header) {
-		if (!no_commit_id)
-			printf("%s%c", header, diff_options.line_termination);
-		header = NULL;
-	}
-	diff_flush(&diff_options);
-	return 1;
-}
-
-static int diff_tree_sha1_top(const unsigned char *old,
-			      const unsigned char *new, const char *base)
-{
-	int ret;
-
-	ret = diff_tree_sha1(old, new, base, &diff_options);
-	call_diff_flush();
-	return ret;
-}
-
-static int diff_root_tree(const unsigned char *new, const char *base)
-{
-	int retval;
-	void *tree;
-	struct tree_desc empty, real;
-
-	tree = read_object_with_reference(new, tree_type, &real.size, NULL);
-	if (!tree)
-		die("unable to read root tree (%s)", sha1_to_hex(new));
-	real.buf = tree;
-
-	empty.buf = "";
-	empty.size = 0;
-	retval = diff_tree(&empty, &real, base, &diff_options);
-	free(tree);
-	call_diff_flush();
-	return retval;
-}
-
-static const char *generate_header(const unsigned char *commit_sha1,
-				   const unsigned char *parent_sha1,
-				   const struct commit *commit)
-{
-	static char this_header[16384];
-	int offset;
-	unsigned long len;
-	int abbrev = diff_options.abbrev;
-	const char *msg = commit->buffer;
-
-	if (!verbose_header)
-		return sha1_to_hex(commit_sha1);
-
-	len = strlen(msg);
-
-	offset = sprintf(this_header, "%s%s ",
-			 header_prefix,
-			 diff_unique_abbrev(commit_sha1, abbrev));
-	if (commit_sha1 != parent_sha1)
-		offset += sprintf(this_header + offset, "(from %s)\n",
-				  parent_sha1
-				  ? diff_unique_abbrev(parent_sha1, abbrev)
-				  : "root");
-	else
-		offset += sprintf(this_header + offset, "(from parents)\n");
-	offset += pretty_print_commit(commit_format, commit, len,
-				      this_header + offset,
-				      sizeof(this_header) - offset, abbrev);
-	if (always_show_header) {
-		puts(this_header);
-		return NULL;
-	}
-	return this_header;
-}
-
-static int diff_tree_commit(struct commit *commit)
-{
-	struct commit_list *parents;
-	unsigned const char *sha1 = commit->object.sha1;
-
-	/* Root commit? */
-	if (show_root_diff && !commit->parents) {
-		header = generate_header(sha1, NULL, commit);
-		diff_root_tree(sha1, "");
-	}
-
-	/* More than one parent? */
-	if (commit->parents && commit->parents->next) {
-		if (ignore_merges)
-			return 0;
-		else if (combine_merges) {
-			header = generate_header(sha1, sha1, commit);
-			header = diff_tree_combined_merge(sha1, header,
-							dense_combined_merges,
-							&diff_options);
-			if (!header && verbose_header)
-				header_prefix = "\ndiff-tree ";
-			return 0;
-		}
-	}
-
-	for (parents = commit->parents; parents; parents = parents->next) {
-		struct commit *parent = parents->item;
-		header = generate_header(sha1, parent->object.sha1, commit);
-		diff_tree_sha1_top(parent->object.sha1, sha1, "");
-		if (!header && verbose_header) {
-			header_prefix = "\ndiff-tree ";
-			/*
-			 * Don't print multiple merge entries if we
-			 * don't print the diffs.
-			 */
-		}
-	}
-	return 0;
-}
+static struct log_tree_opt log_tree_opt;
 
 static int diff_tree_commit_sha1(const unsigned char *sha1)
 {
 	struct commit *commit = lookup_commit_reference(sha1);
 	if (!commit)
 		return -1;
-	return diff_tree_commit(commit);
+	return log_tree_commit(&log_tree_opt, commit);
 }
 
 static int diff_tree_stdin(char *line)
@@ -184,7 +48,7 @@ static int diff_tree_stdin(char *line)
 			pos += 41;
 		}
 	}
-	return diff_tree_commit(commit);
+	return log_tree_commit(&log_tree_opt, commit);
 }
 
 static const char diff_tree_usage[] =
@@ -200,13 +64,15 @@ int main(int argc, const char **argv)
 	char line[1000];
 	unsigned char sha1[2][20];
 	const char *prefix = setup_git_directory();
+	static struct log_tree_opt *opt = &log_tree_opt;
+	int read_stdin = 0;
 
 	git_config(git_diff_config);
 	nr_sha1 = 0;
-	diff_setup(&diff_options);
+	init_log_tree_opt(opt);
 
 	for (;;) {
-		int diff_opt_cnt;
+		int opt_cnt;
 		const char *arg;
 
 		argv++;
@@ -223,84 +89,39 @@ int main(int argc, const char **argv)
 			break;
 		}
 
-		diff_opt_cnt = diff_opt_parse(&diff_options, argv, argc);
-		if (diff_opt_cnt < 0)
+		opt_cnt = log_tree_opt_parse(opt, argv, argc);
+		if (opt_cnt < 0)
 			usage(diff_tree_usage);
-		else if (diff_opt_cnt) {
-			argv += diff_opt_cnt - 1;
-			argc -= diff_opt_cnt - 1;
+		else if (opt_cnt) {
+			argv += opt_cnt - 1;
+			argc -= opt_cnt - 1;
 			continue;
 		}
 
-
 		if (!strcmp(arg, "--")) {
 			argv++;
 			argc--;
 			break;
 		}
-		if (!strcmp(arg, "-r")) {
-			diff_options.recursive = 1;
-			continue;
-		}
-		if (!strcmp(arg, "-t")) {
-			diff_options.recursive = 1;
-			diff_options.tree_in_recursive = 1;
-			continue;
-		}
-		if (!strcmp(arg, "-m")) {
-			ignore_merges = 0;
-			continue;
-		}
-		if (!strcmp(arg, "-c")) {
-			combine_merges = 1;
-			continue;
-		}
-		if (!strcmp(arg, "--cc")) {
-			dense_combined_merges = combine_merges = 1;
-			continue;
-		}
-		if (!strcmp(arg, "-v")) {
-			verbose_header = 1;
-			header_prefix = "diff-tree ";
-			continue;
-		}
-		if (!strncmp(arg, "--pretty", 8)) {
-			verbose_header = 1;
-			header_prefix = "diff-tree ";
-			commit_format = get_commit_format(arg+8);
-			continue;
-		}
 		if (!strcmp(arg, "--stdin")) {
 			read_stdin = 1;
 			continue;
 		}
-		if (!strcmp(arg, "--root")) {
-			show_root_diff = 1;
-			continue;
-		}
-		if (!strcmp(arg, "--no-commit-id")) {
-			no_commit_id = 1;
-			continue;
-		}
-		if (!strcmp(arg, "--always")) {
-			always_show_header = 1;
-			continue;
-		}
 		usage(diff_tree_usage);
 	}
 
-	if (combine_merges)
-		ignore_merges = 0;
+	if (opt->combine_merges)
+		opt->ignore_merges = 0;
 
 	/* We can only do dense combined merges with diff output */
-	if (dense_combined_merges)
-		diff_options.output_format = DIFF_FORMAT_PATCH;
+	if (opt->dense_combined_merges)
+		opt->diffopt.output_format = DIFF_FORMAT_PATCH;
 
-	if (diff_options.output_format == DIFF_FORMAT_PATCH)
-		diff_options.recursive = 1;
+	if (opt->diffopt.output_format == DIFF_FORMAT_PATCH)
+		opt->diffopt.recursive = 1;
 
 	diff_tree_setup_paths(get_pathspec(prefix, argv));
-	diff_setup_done(&diff_options);
+	diff_setup_done(&opt->diffopt);
 
 	switch (nr_sha1) {
 	case 0:
@@ -311,15 +132,16 @@ int main(int argc, const char **argv)
 		diff_tree_commit_sha1(sha1[0]);
 		break;
 	case 2:
-		diff_tree_sha1_top(sha1[0], sha1[1], "");
+		diff_tree_sha1(sha1[0], sha1[1], "", &opt->diffopt);
+		log_tree_diff_flush(opt);
 		break;
 	}
 
 	if (!read_stdin)
 		return 0;
 
-	if (diff_options.detect_rename)
-		diff_options.setup |= (DIFF_SETUP_USE_SIZE_CACHE |
+	if (opt->diffopt.detect_rename)
+		opt->diffopt.setup |= (DIFF_SETUP_USE_SIZE_CACHE |
 				       DIFF_SETUP_USE_CACHE);
 	while (fgets(line, sizeof(line), stdin))
 		diff_tree_stdin(line);