Re: [PATCH 1/2] separate quoting and relative path generation

Clemens Buchacher [off-list ref] writes:

+/* give path as relative to prefix */
+char *path_relative(const char *in, int len,
+		    struct strbuf *out, const char *prefix, int prefix_len)
+{
 	if (len < 0)
 		len = strlen(in);
+	if (prefix && prefix_len < 0)
+		prefix_len = strlen(prefix);
 
 	strbuf_setlen(out, 0);
 	strbuf_grow(out, len);
 
+	if (prefix_len > 0) {
+		int off = 0, i = 0;
+		while (i < prefix_len && i < len && prefix[i] == in[i]) {
+			if (prefix[i] == '/')
+				off = i + 1;
+			i++;
+		}
+		in += off;
+		len -= off;
+
+		while (i < prefix_len) {
+			if (prefix[i] == '/')
 				strbuf_addstr(out, "../");
+			i++;
+		}
 	}
+	strbuf_add(out, in, len);
+
+	return out->buf;
+}

Hmm...  I wonder if we really want to always make a copy of the string in
the majority of the case where there is no need to add ../ and the path
does not have any funny characters that needs quoting.  In such a case,
shouldn't write_name() be just moving the pointers into the original
string to skip the $(cwd) part and writing the remainder of the string
out, without any extra allocation nor copy?  IIUC, that is what the
original did using write_name_quoted().