Re: [PATCH/WIP 5/8] am: detect mbox patches
From: Eric Sunshine <hidden>
Date: 2016-06-15 23:05:04
On Wed, May 27, 2015 at 9:33 AM, Paul Tan [off-list ref] wrote:
Since 15ced75 (git-am foreign patch support: autodetect some patch formats, 2009-05-27), git-am.sh is able to autodetect mbox, stgit and mercurial patches through heuristics. Re-implement support for autodetecting mbox/maildir files.
A few minor comments below...
quoted hunk ↗ jump to hunk
Signed-off-by: Paul Tan <redacted> ---diff --git a/builtin/am.c b/builtin/am.c index 9c7b058..d589ec5 100644 --- a/builtin/am.c +++ b/builtin/am.c@@ -108,6 +108,97 @@ static void am_destroy(const struct am_state *state) strbuf_release(&sb); } +/* + * Returns 1 if the file looks like a piece of email a-la RFC2822, 0 otherwise. + * We check this by grabbing all the non-indented lines and seeing if they look + * like they begin with valid header field names. + */ +static int is_email(const char *filename) +{ + struct strbuf sb = STRBUF_INIT; + FILE *fp = xfopen(filename, "r"); + int ret = 1; + + while (!strbuf_getline(&sb, fp, '\n')) { + const char *x; + + strbuf_rtrim(&sb); + + if (!sb.len) + break; /* End of header */ + + /* Ignore indented folded lines */ + if (*sb.buf == '\t' || *sb.buf == ' ') + continue; + + /* It's a header if it matches the regexp "^[!-9;-~]+:" */ + for (x = sb.buf; *x; x++) { + if (('!' <= *x && *x <= '9') || (';' <= *x && *x <= '~')) + continue; + if (*x == ':' && x != sb.buf) + break; + ret = 0; + goto fail; + } + } + +fail:
It's a bit odd seeing a label named "fail" through which both the successful and failing cases flow. Upon seeing it, I had expected to find a "return 1" somewhere above for the successful case. Perhaps a name such as "done" would be clearer.
+ fclose(fp);
+ strbuf_release(&sb);
+ return ret;
+}
+
+/**
+ * Attempts to detect the patch_format of the patches contained in `paths`,
+ * returning the PATCH_FORMAT_* enum value. Returns PATCH_FORMAT_UNKNOWN if
+ * detection fails.
+ */
+static int detect_patch_format(struct string_list *paths)
+{
+ enum patch_format ret = PATCH_FORMAT_UNKNOWN;
+ struct strbuf l1 = STRBUF_INIT;
+ struct strbuf l2 = STRBUF_INIT;
+ struct strbuf l3 = STRBUF_INIT;
+ FILE *fp;
+
+ /*
+ * We default to mbox format if input is from stdin and for directories
+ */
+ if (!paths->nr || !strcmp(paths->items->string, "-") ||
+ is_directory(paths->items->string)) {
+ strbuf_release(&l1);
+ strbuf_release(&l2);
+ strbuf_release(&l3);
+ return PATCH_FORMAT_MBOX;
A couple observations:
Some people will argue that these strbuf_release() calls are pointless
since the strbufs haven't been used yet, thus should be dropped. (I
don't care strongly.)
Perhaps this case could be a bit less noisy if coded like this:
if (... || ...) {
ret = PATCH_FORMAT_MBOX;
goto done;
}
with a corresponding "done" label added before the strbuf_release()
calls near the bottom of the function.
+ } + + /* + * Otherwise, check the first few 3 lines of the first patch, starting
Either: s/few 3/few/ or s/few 3/3/
quoted hunk ↗ jump to hunk
+ * from the first non-blank line, to try to detect its format. + */ + fp = xfopen(paths->items->string, "r"); + while (!strbuf_getline(&l1, fp, '\n')) { + strbuf_trim(&l1); + if (l1.len) + break; + } + strbuf_getline(&l2, fp, '\n'); + strbuf_trim(&l2); + strbuf_getline(&l3, fp, '\n'); + strbuf_trim(&l3); + fclose(fp); + + if (starts_with(l1.buf, "From ") || starts_with(l1.buf, "From: ")) + ret = PATCH_FORMAT_MBOX; + else if (l1.len && l2.len && l3.len && is_email(paths->items->string)) + ret = PATCH_FORMAT_MBOX; + + strbuf_release(&l1); + strbuf_release(&l2); + strbuf_release(&l3); + return ret; +} + /** * Splits out individual patches from `paths`, where each path is either a mbox * file or a Maildir. Return 0 on success, -1 on failure.@@ -162,6 +253,14 @@ static int split_patches(struct am_state *state, enum patch_format patch_format, static void am_setup(struct am_state *state, enum patch_format patch_format, struct string_list *paths) { + if (!patch_format) + patch_format = detect_patch_format(paths); + + if (!patch_format) { + fprintf_ln(stderr, _("Patch format detection failed.")); + exit(128); + } + if (mkdir(state->dir.buf, 0777) < 0 && errno != EEXIST) die_errno(_("failed to create directory '%s'"), state->dir.buf); --2.1.4