Subject: [PATCHv5 09/17] submodule.c: convert show_submodule_summary to use emit_line_fmt

From: Stefan Beller <[email-masked]>
Date: Wed, 24 May 2017 14:40:28 -0700

In a later patch, I want to propose an option to detect&color
moved lines in a diff, which cannot be done in a one-pass over
the diff. Instead we need to go over the whole diff twice,
because we cannot detect the first line of the two corresponding
lines (+ and -) that got moved.

So to prepare the diff machinery for two pass algorithms
(i.e. buffer it all up and then operate on the result),
move all emissions to places, such that the only emitting
function is emit_line_0.

This prepares the code for submodules to go through the emit_line
function.

As the submodule process is no longer attached to the same stdout as
the superprojects process, one might imagine that we would need to
pass on the usage of colors explicitly as the subprocess can no longer
determine where the output is going to land eventually. But this is not
the case. Apparently coloring submodule diffs never worked, so defer
the submodule diff coloring to a future patch series.

Signed-off-by: Stefan Beller <[email-masked]>
---
 diff.c      | 14 ++++++----
 diff.h      |  3 +++
 submodule.c | 87 ++++++++++++++++++++++++++++++++-----------------------------
 submodule.h |  9 +++----
 4 files changed, 61 insertions(+), 52 deletions(-)

diff --git a/diff.c b/diff.c
index ca6b48cf49..3357c0fca3 100644
--- a/diff.c
+++ b/diff.c
@@ -562,6 +562,12 @@ static void emit_line_fmt(struct diff_options *o,
 	strbuf_release(&sb);
 }
 
+void diff_emit_line(struct diff_options *o, const char *set, const char *reset,
+		    const char *line, int len)
+{
+	emit_line(o, set, reset, 1, 0, line, len);
+}
+
 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 {
 	if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
@@ -2384,8 +2390,7 @@ static void builtin_diff(const char *name_a,
 	    (!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);
@@ -2395,11 +2400,10 @@ static void builtin_diff(const char *name_a,
 		   (!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);
+				meta, del, add, reset);
 		return;
 	}
 
diff --git a/diff.h b/diff.h
index 5be1ee77a7..9ad546361a 100644
--- a/diff.h
+++ b/diff.h
@@ -188,6 +188,9 @@ struct diff_options {
 	int diff_path_counter;
 };
 
+void diff_emit_line(struct diff_options *o, const char *set, const char *reset,
+		    const char *line, int len);
+
 enum color_diff {
 	DIFF_RESET = 0,
 	DIFF_CONTEXT = 1,
diff --git a/submodule.c b/submodule.c
index d3299e29c0..19c63197fb 100644
--- a/submodule.c
+++ b/submodule.c
@@ -362,8 +362,8 @@ 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,
+static void print_submodule_summary(struct rev_info *rev,
+		struct diff_options *o,
 		const char *del, const char *add, const char *reset)
 {
 	static const char format[] = "  %m %s";
@@ -375,18 +375,12 @@ 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_line(o, del, reset, sb.buf, sb.len);
+		else if (add)
+			diff_emit_line(o, add, reset, sb.buf, sb.len);
 	}
 	strbuf_release(&sb);
 }
@@ -413,8 +407,7 @@ 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,
@@ -425,12 +418,17 @@ static void show_submodule_header(FILE *f, const char *path,
 	struct strbuf sb = STRBUF_INIT;
 	int fast_forward = 0, fast_backward = 0;
 
-	if (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED)
-		fprintf(f, "%sSubmodule %s contains untracked content\n",
-			line_prefix, path);
-	if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
-		fprintf(f, "%sSubmodule %s contains modified content\n",
-			line_prefix, path);
+	if (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED) {
+		strbuf_addf(&sb, "Submodule %s contains untracked content\n", path);
+		diff_emit_line(o, NULL, NULL, sb.buf, sb.len);
+		strbuf_reset(&sb);
+	}
+
+	if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED) {
+		strbuf_addf(&sb, "Submodule %s contains modified content\n", path);
+		diff_emit_line(o, NULL, NULL, sb.buf, sb.len);
+		strbuf_reset(&sb);
+	}
 
 	if (is_null_oid(one))
 		message = "(new submodule)";
@@ -472,21 +470,20 @@ 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_line(o, meta, reset, sb.buf, sb.len);
 
 	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)
@@ -495,7 +492,7 @@ void show_submodule_summary(FILE *f, const char *path,
 	struct commit *left = NULL, *right = NULL;
 	struct commit_list *merge_bases = NULL;
 
-	show_submodule_header(f, path, line_prefix, one, two, dirty_submodule,
+	show_submodule_header(o, path, one, two, dirty_submodule,
 			      meta, reset, &left, &right, &merge_bases);
 
 	/*
@@ -508,11 +505,12 @@ 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);
+		const char *error = "(revision walker failed)\n";
+		diff_emit_line(o, NULL, NULL, error, strlen(error));
 		goto out;
 	}
 
-	print_submodule_summary(&rev, f, line_prefix, del, add, reset);
+	print_submodule_summary(&rev, o, del, add, reset);
 
 out:
 	if (merge_bases)
@@ -521,20 +519,18 @@ void show_submodule_summary(FILE *f, const char *path,
 	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)
+		const char *del, const char *add, const char *reset)
 {
 	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,
+	show_submodule_header(o, path, one, two, dirty_submodule,
 			      meta, reset, &left, &right, &merge_bases);
 
 	/* We need a valid left and right commit to display a difference */
@@ -547,15 +543,14 @@ 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_push(&cp.args, "diff");
-	argv_array_pushf(&cp.args, "--line-prefix=%s", line_prefix);
+	argv_array_pushf(&cp.args, "--line-prefix=%s", diff_line_prefix(o));
 	if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
 		argv_array_pushf(&cp.args, "--src-prefix=%s%s/",
 				 o->b_prefix, path);
@@ -578,11 +573,21 @@ 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)) {
+		const char *error = "(diff failed)\n";
+		diff_emit_line(o, NULL, NULL, error, strlen(error));
+	}
+
+	while (strbuf_getwholeline_fd(&sb, cp.out, '\n') != EOF)
+		diff_emit_line(o, NULL, NULL, sb.buf, sb.len);
+
+	if (finish_command(&cp)) {
+		const char *error = "(diff failed)\n";
+		diff_emit_line(o, NULL, NULL, error, strlen(error));
+	}
 
 done:
-	strbuf_release(&submodule_dir);
+	strbuf_release(&sb);
 	if (merge_bases)
 		free_commit_list(merge_bases);
 	if (left)
diff --git a/submodule.h b/submodule.h
index 1277480add..9df0a3aea2 100644
--- a/submodule.h
+++ b/submodule.h
@@ -53,17 +53,14 @@ 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,
+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);
+		const char *del, const char *add, const char *reset);
 extern void set_config_fetch_recurse_submodules(int value);
 extern void set_config_update_recurse_submodules(int value);
 /* Check if we want to update any submodule.*/
-- 
2.13.0.18.g7d86cc8ba0