submodule.c: migrate diff output to use emit_diff_symbol

As the submodule process is no longer attached to the same file pointer
'o->file' as the superprojects process, there is a different result in
color.c::check_auto_color. That is why we need to pass coloring explicitly,
such that the submodule coloring decision will be made by the child process
processing the submodule. Only DIFF_SYMBOL_SUBMODULE_PIPETHROUGH contains
color, the other symbols are for embedding the submodule output into the
superprojects output.

Remove the colors from the function signatures, as all the coloring
decisions will be made either inside the child process or the final
emit_diff_symbol, but not in the functions driving the submodule diff.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff.c

@@ -561,6 +561,13 @@ static void emit_line(struct diff_options *o, const char *set, const char *reset
 }
 
 enum diff_symbol {
+	DIFF_SYMBOL_SUBMODULE_ADD,
+	DIFF_SYMBOL_SUBMODULE_DEL,
+	DIFF_SYMBOL_SUBMODULE_UNTRACKED,
+	DIFF_SYMBOL_SUBMODULE_MODIFIED,
+	DIFF_SYMBOL_SUBMODULE_HEADER,
+	DIFF_SYMBOL_SUBMODULE_ERROR,
+	DIFF_SYMBOL_SUBMODULE_PIPETHROUGH,
 	DIFF_SYMBOL_REWRITE_DIFF,
 	DIFF_SYMBOL_BINARY_FILES,
 	DIFF_SYMBOL_HEADER,
@@ -625,6 +632,9 @@ static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
 		emit_line_0(o, context, reset, '\\',
 			    nneof, strlen(nneof));
 		break;
+	case DIFF_SYMBOL_SUBMODULE_HEADER:
+	case DIFF_SYMBOL_SUBMODULE_ERROR:
+	case DIFF_SYMBOL_SUBMODULE_PIPETHROUGH:
 	case DIFF_SYMBOL_CONTEXT_FRAGINFO:
 		emit_line(o, "", "", line, len);
 		break;
@@ -701,11 +711,68 @@ static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
 		reset = diff_get_color_opt(o, DIFF_RESET);
 		emit_line(o, fraginfo, reset, line, len);
 		break;
+	case DIFF_SYMBOL_SUBMODULE_ADD:
+		set = diff_get_color_opt(o, DIFF_FILE_NEW);
+		reset = diff_get_color_opt(o, DIFF_RESET);
+		emit_line(o, set, reset, line, len);
+		break;
+	case DIFF_SYMBOL_SUBMODULE_DEL:
+		set = diff_get_color_opt(o, DIFF_FILE_OLD);
+		reset = diff_get_color_opt(o, DIFF_RESET);
+		emit_line(o, set, reset, line, len);
+		break;
+	case DIFF_SYMBOL_SUBMODULE_UNTRACKED:
+		fprintf(o->file, "%sSubmodule %s contains untracked content\n",
+			diff_line_prefix(o), line);
+		break;
+	case DIFF_SYMBOL_SUBMODULE_MODIFIED:
+		fprintf(o->file, "%sSubmodule %s contains modified content\n",
+			diff_line_prefix(o), line);
+		break;
 	default:
 		die("BUG: unknown diff symbol");
 	}
 }
 
+void diff_emit_submodule_del(struct diff_options *o, const char *line)
+{
+	emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_DEL, line, strlen(line), 0);
+}
+
+void diff_emit_submodule_add(struct diff_options *o, const char *line)
+{
+	emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ADD, line, strlen(line), 0);
+}
+
+void diff_emit_submodule_untracked(struct diff_options *o, const char *path)
+{
+	emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_UNTRACKED,
+			 path, strlen(path), 0);
+}
+
+void diff_emit_submodule_modified(struct diff_options *o, const char *path)
+{
+	emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_MODIFIED,
+			 path, strlen(path), 0);
+}
+
+void diff_emit_submodule_header(struct diff_options *o, const char *header)
+{
+	emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_HEADER,
+			 header, strlen(header), 0);
+}
+
+void diff_emit_submodule_error(struct diff_options *o, const char *err)
+{
+	emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ERROR, err, strlen(err), 0);
+}
+
+void diff_emit_submodule_pipethrough(struct diff_options *o,
+				     const char *line, int len)
+{
+	emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_PIPETHROUGH, line, len, 0);
+}
+
 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 {
 	if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
@@ -2467,24 +2534,16 @@ static void builtin_diff(const char *name_a,
 	if (o->submodule_format == DIFF_SUBMODULE_LOG &&
 	    (!one->mode || S_ISGITLINK(one->mode)) &&
 	    (!two->mode || S_ISGITLINK(two->mode))) {
-		const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
-		const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
-		show_submodule_summary(o->file, one->path ? one->path : two->path,
-				line_prefix,
+		show_submodule_summary(o, one->path ? one->path : two->path,
 				&one->oid, &two->oid,
-				two->dirty_submodule,
-				meta, del, add, reset);
+				two->dirty_submodule);
 		return;
 	} else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
 		   (!one->mode || S_ISGITLINK(one->mode)) &&
 		   (!two->mode || S_ISGITLINK(two->mode))) {
-		const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
-		const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
-		show_submodule_inline_diff(o->file, one->path ? one->path : two->path,
-				line_prefix,
+		show_submodule_inline_diff(o, one->path ? one->path : two->path,
 				&one->oid, &two->oid,
-				two->dirty_submodule,
-				meta, del, add, reset, o);
+				two->dirty_submodule);
 		return;
 	}
 

diff.h

@@ -188,6 +188,15 @@ struct diff_options {
 	int diff_path_counter;
 };
 
+void diff_emit_submodule_del(struct diff_options *o, const char *line);
+void diff_emit_submodule_add(struct diff_options *o, const char *line);
+void diff_emit_submodule_untracked(struct diff_options *o, const char *path);
+void diff_emit_submodule_modified(struct diff_options *o, const char *path);
+void diff_emit_submodule_header(struct diff_options *o, const char *header);
+void diff_emit_submodule_error(struct diff_options *o, const char *err);
+void diff_emit_submodule_pipethrough(struct diff_options *o,
+				     const char *line, int len);
+
 enum color_diff {
 	DIFF_RESET = 0,
 	DIFF_CONTEXT = 1,

submodule.c

@@ -479,9 +479,7 @@ static int prepare_submodule_summary(struct rev_info *rev, const char *path,
 	return prepare_revision_walk(rev);
 }
 
-static void print_submodule_summary(struct rev_info *rev, FILE *f,
-		const char *line_prefix,
-		const char *del, const char *add, const char *reset)
+static void print_submodule_summary(struct rev_info *rev, struct diff_options *o)
 {
 	static const char format[] = "  %m %s";
 	struct strbuf sb = STRBUF_INIT;
@@ -492,18 +490,12 @@ static void print_submodule_summary(struct rev_info *rev, FILE *f,
 		ctx.date_mode = rev->date_mode;
 		ctx.output_encoding = get_log_output_encoding();
 		strbuf_setlen(&sb, 0);
-		strbuf_addstr(&sb, line_prefix);
-		if (commit->object.flags & SYMMETRIC_LEFT) {
-			if (del)
-				strbuf_addstr(&sb, del);
-		}
-		else if (add)
-			strbuf_addstr(&sb, add);
 		format_commit_message(commit, format, &sb, &ctx);
-		if (reset)
-			strbuf_addstr(&sb, reset);
 		strbuf_addch(&sb, '\n');
-		fprintf(f, "%s", sb.buf);
+		if (commit->object.flags & SYMMETRIC_LEFT)
+			diff_emit_submodule_del(o, sb.buf);
+		else
+			diff_emit_submodule_add(o, sb.buf);
 	}
 	strbuf_release(&sb);
 }
@@ -530,11 +522,9 @@ void prepare_submodule_repo_env(struct argv_array *out)
  * attempt to lookup both the left and right commits and put them into the
  * left and right pointers.
  */
-static void show_submodule_header(FILE *f, const char *path,
-		const char *line_prefix,
+static void show_submodule_header(struct diff_options *o, const char *path,
 		struct object_id *one, struct object_id *two,
-		unsigned dirty_submodule, const char *meta,
-		const char *reset,
+		unsigned dirty_submodule,
 		struct commit **left, struct commit **right,
 		struct commit_list **merge_bases)
 {
@@ -543,11 +533,10 @@ static void show_submodule_header(FILE *f, const char *path,
 	int fast_forward = 0, fast_backward = 0;
 
 	if (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED)
-		fprintf(f, "%sSubmodule %s contains untracked content\n",
-			line_prefix, path);
+		diff_emit_submodule_untracked(o, path);
+
 	if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
-		fprintf(f, "%sSubmodule %s contains modified content\n",
-			line_prefix, path);
+		diff_emit_submodule_modified(o, path);
 
 	if (is_null_oid(one))
 		message = "(new submodule)";
@@ -589,31 +578,29 @@ static void show_submodule_header(FILE *f, const char *path,
 	}
 
 output_header:
-	strbuf_addf(&sb, "%s%sSubmodule %s ", line_prefix, meta, path);
+	strbuf_addf(&sb, "Submodule %s ", path);
 	strbuf_add_unique_abbrev(&sb, one->hash, DEFAULT_ABBREV);
 	strbuf_addstr(&sb, (fast_backward || fast_forward) ? ".." : "...");
 	strbuf_add_unique_abbrev(&sb, two->hash, DEFAULT_ABBREV);
 	if (message)
-		strbuf_addf(&sb, " %s%s\n", message, reset);
+		strbuf_addf(&sb, " %s\n", message);
 	else
-		strbuf_addf(&sb, "%s:%s\n", fast_backward ? " (rewind)" : "", reset);
-	fwrite(sb.buf, sb.len, 1, f);
+		strbuf_addf(&sb, "%s:\n", fast_backward ? " (rewind)" : "");
+	diff_emit_submodule_header(o, sb.buf);
 
 	strbuf_release(&sb);
 }
 
-void show_submodule_summary(FILE *f, const char *path,
-		const char *line_prefix,
+void show_submodule_summary(struct diff_options *o, const char *path,
 		struct object_id *one, struct object_id *two,
-		unsigned dirty_submodule, const char *meta,
-		const char *del, const char *add, const char *reset)
+		unsigned dirty_submodule)
 {
 	struct rev_info rev;
 	struct commit *left = NULL, *right = NULL;
 	struct commit_list *merge_bases = NULL;
 
-	show_submodule_header(f, path, line_prefix, one, two, dirty_submodule,
-			      meta, reset, &left, &right, &merge_bases);
+	show_submodule_header(o, path, one, two, dirty_submodule,
+			      &left, &right, &merge_bases);
 
 	/*
 	 * If we don't have both a left and a right pointer, there is no
@@ -625,11 +612,11 @@ void show_submodule_summary(FILE *f, const char *path,
 
 	/* Treat revision walker failure the same as missing commits */
 	if (prepare_submodule_summary(&rev, path, left, right, merge_bases)) {
-		fprintf(f, "%s(revision walker failed)\n", line_prefix);
+		diff_emit_submodule_error(o, "(revision walker failed)\n");
 		goto out;
 	}
 
-	print_submodule_summary(&rev, f, line_prefix, del, add, reset);
+	print_submodule_summary(&rev, o);
 
 out:
 	if (merge_bases)
@@ -638,21 +625,18 @@ out:
 	clear_commit_marks(right, ~0);
 }
 
-void show_submodule_inline_diff(FILE *f, const char *path,
-		const char *line_prefix,
+void show_submodule_inline_diff(struct diff_options *o, const char *path,
 		struct object_id *one, struct object_id *two,
-		unsigned dirty_submodule, const char *meta,
-		const char *del, const char *add, const char *reset,
-		const struct diff_options *o)
+		unsigned dirty_submodule)
 {
 	const struct object_id *old = &empty_tree_oid, *new = &empty_tree_oid;
 	struct commit *left = NULL, *right = NULL;
 	struct commit_list *merge_bases = NULL;
-	struct strbuf submodule_dir = STRBUF_INIT;
 	struct child_process cp = CHILD_PROCESS_INIT;
+	struct strbuf sb = STRBUF_INIT;
 
-	show_submodule_header(f, path, line_prefix, one, two, dirty_submodule,
-			      meta, reset, &left, &right, &merge_bases);
+	show_submodule_header(o, path, one, two, dirty_submodule,
+			      &left, &right, &merge_bases);
 
 	/* We need a valid left and right commit to display a difference */
 	if (!(left || is_null_oid(one)) ||
@@ -664,16 +648,16 @@ void show_submodule_inline_diff(FILE *f, const char *path,
 	if (right)
 		new = two;
 
-	fflush(f);
 	cp.git_cmd = 1;
 	cp.dir = path;
-	cp.out = dup(fileno(f));
+	cp.out = -1;
 	cp.no_stdin = 1;
 
 	/* TODO: other options may need to be passed here. */
 	argv_array_pushl(&cp.args, "diff", "--submodule=diff", NULL);
+	argv_array_pushf(&cp.args, "--color=%s", want_color(o->use_color) ?
+			 "always" : "never");
 
-	argv_array_pushf(&cp.args, "--line-prefix=%s", line_prefix);
 	if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
 		argv_array_pushf(&cp.args, "--src-prefix=%s%s/",
 				 o->b_prefix, path);
@@ -696,11 +680,17 @@ void show_submodule_inline_diff(FILE *f, const char *path,
 		argv_array_push(&cp.args, oid_to_hex(new));
 
 	prepare_submodule_repo_env(&cp.env_array);
-	if (run_command(&cp))
-		fprintf(f, "(diff failed)\n");
+	if (start_command(&cp))
+		diff_emit_submodule_error(o, "(diff failed)\n");
+
+	while (strbuf_getwholeline_fd(&sb, cp.out, '\n') != EOF)
+		diff_emit_submodule_pipethrough(o, sb.buf, sb.len);
+
+	if (finish_command(&cp))
+		diff_emit_submodule_error(o, "(diff failed)\n");
 
 done:
-	strbuf_release(&submodule_dir);
+	strbuf_release(&sb);
 	if (merge_bases)
 		free_commit_list(merge_bases);
 	if (left)

submodule.h

@@ -63,17 +63,12 @@ extern int parse_submodule_update_strategy(const char *value,
 		struct submodule_update_strategy *dst);
 extern const char *submodule_strategy_to_string(const struct submodule_update_strategy *s);
 extern void handle_ignore_submodules_arg(struct diff_options *, const char *);
-extern void show_submodule_summary(FILE *f, const char *path,
-		const char *line_prefix,
+extern void show_submodule_summary(struct diff_options *o, const char *path,
 		struct object_id *one, struct object_id *two,
-		unsigned dirty_submodule, const char *meta,
-		const char *del, const char *add, const char *reset);
-extern void show_submodule_inline_diff(FILE *f, const char *path,
-		const char *line_prefix,
+		unsigned dirty_submodule);
+extern void show_submodule_inline_diff(struct diff_options *o, const char *path,
 		struct object_id *one, struct object_id *two,
-		unsigned dirty_submodule, const char *meta,
-		const char *del, const char *add, const char *reset,
-		const struct diff_options *opt);
+		unsigned dirty_submodule);
 extern void set_config_fetch_recurse_submodules(int value);
 /* Check if we want to update any submodule.*/
 extern int should_update_submodules(void);