log: prepare log/log-tree to reuse the diffopt.close_file attribute

We are about to teach the log-tree machinery to reuse the diffopt.file
field to output to a file stream other than stdout, in line with the
diff machinery already writing to diffopt.file.

However, we might want to write something after the diff in
log_tree_commit() (e.g. with the --show-linear-break option), therefore
we must not let the diff machinery close the file (as per
diffopt.close_file.

This means that log_tree_commit() itself must override the
diffopt.close_file flag and close the file, and if log_tree_commit() is
called in a loop, the caller is responsible to do the same.

Note: format-patch has an `--output-directory` option. Due to the fact
that format-patch's options are parsed first, and that the parse-options
machinery accepts uniquely abbreviated options, the diff options
`--output` (and `-o`) are shadowed. Therefore close_file is not set to 1
so that cmd_format_patch() does *not* need to handle the close_file flag
differently, even if it calls log_tree_commit() in a loop.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/log.c

@@ -243,9 +243,10 @@ static struct itimerval early_output_timer;
 
 static void log_show_early(struct rev_info *revs, struct commit_list *list)
 {
-	int i = revs->early_output;
+	int i = revs->early_output, close_file = revs->diffopt.close_file;
 	int show_header = 1;
 
+	revs->diffopt.close_file = 0;
 	sort_in_topological_order(&list, revs->sort_order);
 	while (list && i) {
 		struct commit *commit = list->item;
@@ -262,14 +263,19 @@ static void log_show_early(struct rev_info *revs, struct commit_list *list)
 		case commit_ignore:
 			break;
 		case commit_error:
+			if (close_file)
+				fclose(revs->diffopt.file);
 			return;
 		}
 		list = list->next;
 	}
 
 	/* Did we already get enough commits for the early output? */
-	if (!i)
+	if (!i) {
+		if (close_file)
+			fclose(revs->diffopt.file);
 		return;
+	}
 
 	/*
 	 * ..if no, then repeat it twice a second until we
@@ -331,7 +337,7 @@ static int cmd_log_walk(struct rev_info *rev)
 {
 	struct commit *commit;
 	int saved_nrl = 0;
-	int saved_dcctc = 0;
+	int saved_dcctc = 0, close_file = rev->diffopt.close_file;
 
 	if (rev->early_output)
 		setup_early_output(rev);
@@ -347,6 +353,7 @@ static int cmd_log_walk(struct rev_info *rev)
 	 * and HAS_CHANGES being accumulated in rev->diffopt, so be careful to
 	 * retain that state information if replacing rev->diffopt in this loop
 	 */
+	rev->diffopt.close_file = 0;
 	while ((commit = get_revision(rev)) != NULL) {
 		if (!log_tree_commit(rev, commit) && rev->max_count >= 0)
 			/*
@@ -367,6 +374,8 @@ static int cmd_log_walk(struct rev_info *rev)
 	}
 	rev->diffopt.degraded_cc_to_c = saved_dcctc;
 	rev->diffopt.needed_rename_limit = saved_nrl;
+	if (close_file)
+		fclose(rev->diffopt.file);
 
 	if (rev->diffopt.output_format & DIFF_FORMAT_CHECKDIFF &&
 	    DIFF_OPT_TST(&rev->diffopt, CHECK_FAILED)) {

log-tree.c

@@ -862,11 +862,12 @@ static int log_tree_diff(struct rev_info *opt, struct commit *commit, struct log
 int log_tree_commit(struct rev_info *opt, struct commit *commit)
 {
 	struct log_info log;
-	int shown;
+	int shown, close_file = opt->diffopt.close_file;
 
 	log.commit = commit;
 	log.parent = NULL;
 	opt->loginfo = &log;
+	opt->diffopt.close_file = 0;
 
 	if (opt->line_level_traverse)
 		return line_log_print(opt, commit);
@@ -883,5 +884,7 @@ int log_tree_commit(struct rev_info *opt, struct commit *commit)
 		printf("\n%s\n", opt->break_bar);
 	opt->loginfo = NULL;
 	maybe_flush_or_die(stdout, "stdout");
+	if (close_file)
+		fclose(opt->diffopt.file);
 	return shown;
 }