On 07/05, Johannes Schindelin wrote:

Hi Thomas,


On Fri, 5 Jul 2019, Thomas Gummerer wrote:

quoted

Currently range-diff uses the 'strbuf_getline()' function for doing
its line by line processing.  In a future patch we want to do parts of
that parsing using the 'parse_git_header()' function, which does

If you like my suggestion in patch 7/14, this commit message needs to talk
about the new name, too.

Thanks for the reminder here!  I do indeed like the new name, but
would probably have forgotten to change it in the commit message here.

quoted

requires reading parts of the input from that function, which doesn't

s/requires/require/

quoted

use strbufs.

Switch range-diff to do our own line by line parsing, so we can re-use
the parse_git_header function later.

Signed-off-by: Thomas Gummerer <redacted>
---

Longer term it might be better to have both range-diff and apply code
use strbufs.  However I didn't feel it's worth making that change for
this patch series.

Makes sense.

quoted

 range-diff.c | 69 +++++++++++++++++++++++++++++-----------------------
 1 file changed, 39 insertions(+), 30 deletions(-)

diff --git a/range-diff.c b/range-diff.c
index 9242b8975f..916afa44c0 100644
--- a/range-diff.c
+++ b/range-diff.c

@@ -24,6 +24,17 @@ struct patch_util {
 	struct object_id oid;
 };

+static unsigned long linelen(const char *buffer, unsigned long size)

Shouldn't this be `size_t`?

quoted

+{
+	unsigned long len = 0;

Likewise.

quoted

+	while (size--) {
+		len++;
+		if (*buffer++ == '\n')
+			break;
+	}
+	return len;

How about

	const char *eol = memchr(buffer, '\n', size);

	return !eol ? size : eol + 1 - buffer;

instead?

For an extra brownie point, you could even rename this function to
`find_end_of_line()` and replace the LF by a NUL:

	if (!eol)
		return size;

	*eol = '\0';
	return eol + 1 - buffer;

I like this, thank you!

quoted

+}
+
 /*
  * Reads the patches into a string list, with the `util` field being populated
  * as struct object_id (will need to be free()d).

@@ -31,10 +42,12 @@ struct patch_util {
 static int read_patches(const char *range, struct string_list *list)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
-	FILE *in;
-	struct strbuf buf = STRBUF_INIT, line = STRBUF_INIT;
+	struct strbuf buf = STRBUF_INIT, file = STRBUF_INIT;

This puzzled me. I'd like to suggest s/file/contents/

Thanks, will change.

quoted

 	struct patch_util *util = NULL;
 	int in_header = 1;
+	char *line;
+	int offset, len;
+	size_t size;

 	argv_array_pushl(&cp.args, "log", "--no-color", "-p", "--no-merges",
 			"--reverse", "--date-order", "--decorate=no",

@@ -54,17 +67,15 @@ static int read_patches(const char *range, struct string_list *list)

 	if (start_command(&cp))
 		return error_errno(_("could not start `log`"));
-	in = fdopen(cp.out, "r");
-	if (!in) {
-		error_errno(_("could not read `log` output"));
-		finish_command(&cp);
-		return -1;
-	}
+	strbuf_read(&file, cp.out, 0);

Shouldn't we handle a negative return value here, erroring out with "could
not read `log` output" as before?

Yeah, that was an oversight, we should definitely still handle errors
here.

quoted

-	while (strbuf_getline(&line, in) != EOF) {
+	line = strbuf_detach(&file, &size);

I strongly suspect this to leak, given that `line` is subsequently
advanced, and there is no backup copy.

Maybe

	line = file.buf;
	size = file.len;

would make more sense here?

Hmm good point, that makes more sense indeed.

quoted

+	for (offset = 0; size > 0; offset += len, size -= len, line += len) {
 		const char *p;

-		if (skip_prefix(line.buf, "commit ", &p)) {
+		len = linelen(line, size);
+		line[len - 1] = '\0';
+		if (skip_prefix(line, "commit ", &p)) {
 			if (util) {
 				string_list_append(list, buf.buf)->util = util;
 				strbuf_reset(&buf);

@@ -75,8 +86,6 @@ static int read_patches(const char *range, struct string_list *list)
 				free(util);
 				string_list_clear(list, 1);
 				strbuf_release(&buf);
-				strbuf_release(&line);
-				fclose(in);

We should release the file contents in `file` (or `contents`, if you like
my suggestions) here.

Yeah, I thought it was no longer necessary because of the
'strbuf_detach()' earlier, but that obviously leaks in a different way
as you pointed out.  Will release 'contents' here and below. 

quoted

 				finish_command(&cp);
 				return -1;
 			}

@@ -85,26 +94,28 @@ static int read_patches(const char *range, struct string_list *list)
 			continue;
 		}

-		if (starts_with(line.buf, "diff --git")) {
+		if (starts_with(line, "diff --git")) {
 			in_header = 0;
 			strbuf_addch(&buf, '\n');
 			if (!util->diff_offset)
 				util->diff_offset = buf.len;
 			strbuf_addch(&buf, ' ');
-			strbuf_addbuf(&buf, &line);
+			strbuf_addstr(&buf, line);
 		} else if (in_header) {
-			if (starts_with(line.buf, "Author: ")) {
-				strbuf_addbuf(&buf, &line);
+			if (starts_with(line, "Author: ")) {
+				strbuf_addstr(&buf, line);
 				strbuf_addstr(&buf, "\n\n");
-			} else if (starts_with(line.buf, "    ")) {
-				strbuf_rtrim(&line);
-				strbuf_addbuf(&buf, &line);
+			} else if (starts_with(line, "    ")) {
+				p = line + len - 2;
+				while (isspace(*p) && p >= line)
+					p--;
+				strbuf_add(&buf, line, p - line + 1);
 				strbuf_addch(&buf, '\n');
 			}
 			continue;
-		} else if (starts_with(line.buf, "@@ "))
+		} else if (starts_with(line, "@@ "))
 			strbuf_addstr(&buf, "@@");
-		else if (!line.buf[0] || starts_with(line.buf, "index "))
+		else if (!line[0] || starts_with(line, "index "))
 			/*
 			 * A completely blank (not ' \n', which is context)
 			 * line is not valid in a diff.  We skip it

@@ -117,25 +128,23 @@ static int read_patches(const char *range, struct string_list *list)
 			 * we are not interested.
 			 */
 			continue;
-		else if (line.buf[0] == '>') {
+		else if (line[0] == '>') {
 			strbuf_addch(&buf, '+');
-			strbuf_add(&buf, line.buf + 1, line.len - 1);
-		} else if (line.buf[0] == '<') {
+			strbuf_addstr(&buf, line + 1);
+		} else if (line[0] == '<') {
 			strbuf_addch(&buf, '-');
-			strbuf_add(&buf, line.buf + 1, line.len - 1);
-		} else if (line.buf[0] == '#') {
+			strbuf_addstr(&buf, line + 1);
+		} else if (line[0] == '#') {
 			strbuf_addch(&buf, ' ');
-			strbuf_add(&buf, line.buf + 1, line.len - 1);
+			strbuf_addstr(&buf, line + 1);
 		} else {
 			strbuf_addch(&buf, ' ');
-			strbuf_addbuf(&buf, &line);
+			strbuf_addstr(&buf, line);
 		}

 		strbuf_addch(&buf, '\n');
 		util->diffsize++;
 	}
-	fclose(in);
-	strbuf_release(&line);

We should release the file contents we previously read via `strbuf_read()` here.

Ciao,
Dscho

quoted

 	if (util)
 		string_list_append(list, buf.buf)->util = util;
--
2.22.0.510.g264f2c817a