On 07/05, Johannes Schindelin wrote:
> Hi Thomas,
>
>
> On Fri, 5 Jul 2019, Thomas Gummerer wrote:
>
> > 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.
> > requires reading parts of the input from that function, which doesn't
>
> s/requires/require/
>
> > 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 <t.gummerer@xxxxxxxxx>
> > ---
> >
> > 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.
>
> > 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`?
>
> > +{
> > + unsigned long len = 0;
>
> Likewise.
>
> > + 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!
> > +}
> > +
> > /*
> > * 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.
> > 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.
> >
> > - 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.
> > + 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.
> > 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
>
> >
> > if (util)
> > string_list_append(list, buf.buf)->util = util;
> > --
> > 2.22.0.510.g264f2c817a
> >
> >
