Re: [PATCH v4 4/5] fast-export: do not modify memory from get_commit_buffer

Luke Shumaker [off-list ref] writes:

+static char *reencode_message(const char *in_msg,
+			      const char *in_encoding, size_t in_encoding_len)
+{
+	static struct strbuf in_encoding_buf = STRBUF_INIT;
+
+	strbuf_reset(&in_encoding_buf);
+	strbuf_add(&in_encoding_buf, in_encoding, in_encoding_len);
+
+	return reencode_string(in_msg, "UTF-8", in_encoding_buf.buf);
+}

There is only a single caller of this, so making it caller's
responsibility to do the strbuf thing would allow us to make this
thread-safe quite easily (and at that point we might not even have
this helper function).

+	committer = strstr(commit_buffer_cursor, "\ncommitter ");
 	if (!committer)
 		die("could not find committer in commit %s",
 		    oid_to_hex(&commit->object.oid));
 	committer++;
-	committer_end = strchrnul(committer, '\n');
-	message = strstr(committer_end, "\n\n");
-	encoding = find_encoding(committer_end, message);
+	commit_buffer_cursor = committer_end = strchrnul(committer, '\n');
+
+	/* find_commit_header() gets a `+ 1` because
+	 * commit_buffer_cursor points at the trailing "\n" at the end
+	 * of the previous line, but find_commit_header() wants a
+	 * pointer to the beginning of the next line. */
+	encoding = find_commit_header(commit_buffer_cursor + 1, "encoding", &encoding_len);

	/*
	 * Our multi-line comments have opening and closing
	 * slash-asterisk and asterisk-slash on their own
	 * lines.
	 */

What if strchrnul() returned a pointer to the terminating NUL
instead of the LF at the end of the line?  +1 will run past the end
of the buffer.

+	if (encoding)
+		commit_buffer_cursor = encoding + encoding_len;
+
+	message = strstr(commit_buffer_cursor, "\n\n");

Good.

Here is where we can do the temporary strbuf to hold encoding[0,
encoding_len] and directly call reencode_string().

Other than that, this step looks good to me.

Thanks.