Full rework of quote_c_style and write_name_quoted.

* quote_c_style works on a strbuf instead of a wild buffer.
* quote_c_style is now clever enough to not add double quotes if not needed.

* write_name_quoted inherits those advantages, but also take a different
  set of arguments. Now instead of asking for quotes or not, you pass a
  "terminator". If it's \0 then we assume you don't want to escape, else C
  escaping is performed. In any case, the terminator is also appended to the
  stream. It also no longer takes the prefix/prefix_len arguments, as it's
  seldomly used, and makes some optimizations harder.

* write_name_quotedpfx is created to work like write_name_quoted and take
  the prefix/prefix_len arguments.

Thanks to those API changes, diff.c has somehow lost weight, thanks to the
removal of functions that were wrappers around the old write_name_quoted
trying to give it a semantics like the new one, but performing a lot of
allocations for this goal. Now we always write directly to the stream, no
intermediate allocation is performed.

As a side effect of the refactor in builtin-apply.c, the length of the bar
graphs in diffstats are not affected anymore by the fact that the path was
clipped.

Signed-off-by: Pierre Habouzit <madcoder@debian.org>

builtin-apply.c

@@ -163,15 +163,14 @@ static void say_patch_name(FILE *output, const char *pre, struct patch *patch, c
 	fputs(pre, output);
 	if (patch->old_name && patch->new_name &&
 	    strcmp(patch->old_name, patch->new_name)) {
-		write_name_quoted(NULL, 0, patch->old_name, 1, output);
+		quote_c_style(patch->old_name, NULL, output, 0);
 		fputs(" => ", output);
-		write_name_quoted(NULL, 0, patch->new_name, 1, output);
-	}
-	else {
+		quote_c_style(patch->new_name, NULL, output, 0);
+	} else {
 		const char *n = patch->new_name;
 		if (!n)
 			n = patch->old_name;
-		write_name_quoted(NULL, 0, n, 1, output);
+		quote_c_style(n, NULL, output, 0);
 	}
 	fputs(post, output);
 }
@@ -1379,61 +1378,50 @@ static const char minuses[]= "--------------------------------------------------
 
 static void show_stats(struct patch *patch)
 {
-	const char *prefix = "";
-	char *name = patch->new_name;
-	char *qname = NULL;
-	int len, max, add, del, total;
-
-	if (!name)
-		name = patch->old_name;
+	struct strbuf qname;
+	char *cp = patch->new_name ? patch->new_name : patch->old_name;
+	int max, add, del;
 
-	if (0 < (len = quote_c_style(name, NULL, NULL, 0))) {
-		qname = xmalloc(len + 1);
-		quote_c_style(name, qname, NULL, 0);
-		name = qname;
-	}
+	strbuf_init(&qname, 0);
+	quote_c_style(cp, &qname, NULL, 0);
 
 	/*
 	 * "scale" the filename
 	 */
-	len = strlen(name);
 	max = max_len;
 	if (max > 50)
 		max = 50;
-	if (len > max) {
-		char *slash;
-		prefix = "...";
-		max -= 3;
-		name += len - max;
-		slash = strchr(name, '/');
-		if (slash)
-			name = slash;
+
+	if (qname.len > max) {
+		cp = strchr(qname.buf + qname.len + 3 - max, '/');
+		if (!cp)
+			cp = qname.buf + qname.len + 3 - max;
+		strbuf_splice(&qname, 0, cp - qname.buf, "...", 3);
+	}
+
+	if (patch->is_binary) {
+		printf(" %-*s |  Bin\n", max, qname.buf);
+		strbuf_release(&qname);
+		return;
 	}
-	len = max;
+
+	printf(" %-*s |", max, qname.buf);
+	strbuf_release(&qname);
 
 	/*
 	 * scale the add/delete
 	 */
-	max = max_change;
-	if (max + len > 70)
-		max = 70 - len;
-
+	max = max + max_change > 70 ? 70 - max : max_change;
 	add = patch->lines_added;
 	del = patch->lines_deleted;
-	total = add + del;
 
 	if (max_change > 0) {
-		total = (total * max + max_change / 2) / max_change;
+		int total = ((add + del) * max + max_change / 2) / max_change;
 		add = (add * max + max_change / 2) / max_change;
 		del = total - add;
 	}
-	if (patch->is_binary)
-		printf(" %s%-*s |  Bin\n", prefix, len, name);
-	else
-		printf(" %s%-*s |%5d %.*s%.*s\n", prefix,
-		       len, name, patch->lines_added + patch->lines_deleted,
-		       add, pluses, del, minuses);
-	free(qname);
+	printf("%5d %.*s%.*s\n", patch->lines_added + patch->lines_deleted,
+		add, pluses, del, minuses);
 }
 
 static int read_old_data(struct stat *st, const char *path, struct strbuf *buf)
@@ -2228,13 +2216,8 @@ static void numstat_patch_list(struct patch *patch)
 		if (patch->is_binary)
 			printf("-\t-\t");
 		else
-			printf("%d\t%d\t",
-			       patch->lines_added, patch->lines_deleted);
-		if (line_termination && quote_c_style(name, NULL, NULL, 0))
-			quote_c_style(name, NULL, stdout, 0);
-		else
-			fputs(name, stdout);
-		putchar(line_termination);
+			printf("%d\t%d\t", patch->lines_added, patch->lines_deleted);
+		write_name_quoted(name, stdout, line_termination);
 	}
 }
 

builtin-blame.c

@@ -1430,8 +1430,7 @@ static void get_commit_info(struct commit *commit,
 static void write_filename_info(const char *path)
 {
 	printf("filename ");
-	write_name_quoted(NULL, 0, path, 1, stdout);
-	putchar('\n');
+	write_name_quoted(path, stdout, '\n');
 }
 
 /*

builtin-check-attr.c

@@ -56,7 +56,7 @@ int cmd_check_attr(int argc, const char **argv, const char *prefix)
 			else if (ATTR_UNSET(value))
 				value = "unspecified";
 
-			write_name_quoted("", 0, argv[i], 1, stdout);
+			quote_c_style(argv[i], NULL, stdout, 0);
 			printf(": %s: %s\n", argv[j+1], value);
 		}
 	}

builtin-checkout-index.c

@@ -66,9 +66,7 @@ static void write_tempfile_record(const char *name, int prefix_length)
 		fputs(topath[checkout_stage], stdout);
 
 	putchar('\t');
-	write_name_quoted("", 0, name + prefix_length,
-		line_termination, stdout);
-	putchar(line_termination);
+	write_name_quoted(name + prefix_length, stdout, line_termination);
 
 	for (i = 0; i < 4; i++) {
 		topath[i][0] = 0;

builtin-ls-files.c

@@ -84,8 +84,7 @@ static void show_dir_entry(const char *tag, struct dir_entry *ent)
 		return;
 
 	fputs(tag, stdout);
-	write_name_quoted("", 0, ent->name + offset, line_terminator, stdout);
-	putchar(line_terminator);
+	write_name_quoted(ent->name + offset, stdout, line_terminator);
 }
 
 static void show_other_files(struct dir_struct *dir)
@@ -208,21 +207,15 @@ static void show_ce_entry(const char *tag, struct cache_entry *ce)
 
 	if (!show_stage) {
 		fputs(tag, stdout);
-		write_name_quoted("", 0, ce->name + offset,
-				  line_terminator, stdout);
-		putchar(line_terminator);
-	}
-	else {
+	} else {
 		printf("%s%06o %s %d\t",
 		       tag,
 		       ntohl(ce->ce_mode),
 		       abbrev ? find_unique_abbrev(ce->sha1,abbrev)
 				: sha1_to_hex(ce->sha1),
 		       ce_stage(ce));
-		write_name_quoted("", 0, ce->name + offset,
-				  line_terminator, stdout);
-		putchar(line_terminator);
 	}
+	write_name_quoted(ce->name + offset, stdout, line_terminator);
 }
 
 static void show_files(struct dir_struct *dir, const char *prefix)

builtin-ls-tree.c

@@ -112,10 +112,8 @@ static int show_tree(const unsigned char *sha1, const char *base, int baselen,
 			       abbrev ? find_unique_abbrev(sha1, abbrev)
 			              : sha1_to_hex(sha1));
 	}
-	write_name_quoted(base + chomp_prefix, baselen - chomp_prefix,
-			  pathname,
-			  line_termination, stdout);
-	putchar(line_termination);
+	write_name_quotedpfx(base + chomp_prefix, baselen - chomp_prefix,
+			  pathname, stdout, line_termination);
 	return retval;
 }
 

combine-diff.c

@@ -650,10 +650,7 @@ static void dump_quoted_path(const char *prefix, const char *path,
 			     const char *c_meta, const char *c_reset)
 {
 	printf("%s%s", c_meta, prefix);
-	if (quote_c_style(path, NULL, NULL, 0))
-		quote_c_style(path, NULL, stdout, 0);
-	else
-		printf("%s", path);
+	quote_c_style(path, NULL, stdout, 0);
 	printf("%s\n", c_reset);
 }
 
@@ -900,16 +897,7 @@ static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct re
 		putchar(inter_name_termination);
 	}
 
-	if (line_termination) {
-		if (quote_c_style(p->path, NULL, NULL, 0))
-			quote_c_style(p->path, NULL, stdout, 0);
-		else
-			printf("%s", p->path);
-		putchar(line_termination);
-	}
-	else {
-		printf("%s%c", p->path, line_termination);
-	}
+	write_name_quoted(p->path, stdout, line_termination);
 }
 
 void show_combined_diff(struct combine_diff_path *p,