strbuf: factor out strbuf_expand_step()

Extract the part of strbuf_expand that finds the next placeholder into a
new function.  It allows to build parsers without callback functions and
the overhead imposed by them.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/branch.c b/builtin/branch.c
index e6c2655af68b339a7aa863cedd6d75e5176dd443..7c20e049a23abf3418f8e85fdc7662e78fcee7ab 100644 (file)
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -366,17 +366,8 @@ static const char *quote_literal_for_format(const char *s)
        static struct strbuf buf = STRBUF_INIT;
 
        strbuf_reset(&buf);
-       while (*s) {
-               const char *ep = strchrnul(s, '%');
-               if (s < ep)
-                       strbuf_add(&buf, s, ep - s);
-               if (*ep == '%') {
-                       strbuf_addstr(&buf, "%%");
-                       s = ep + 1;
-               } else {
-                       s = ep;
-               }
-       }
+       while (strbuf_expand_step(&buf, &s))
+               strbuf_addstr(&buf, "%%");
        return buf.buf;
 }
 

diff --git a/strbuf.c b/strbuf.c
index 08eec8f1d8b488fe9040b219edae353b4d199077..a90b597da10c6f1bce48d84d610e43db44e4807d 100644 (file)
--- a/strbuf.c
+++ b/strbuf.c
@@ -415,19 +415,24 @@ void strbuf_vaddf(struct strbuf *sb, const char *fmt, va_list ap)
        strbuf_setlen(sb, sb->len + len);
 }
 
+int strbuf_expand_step(struct strbuf *sb, const char **formatp)
+{
+       const char *format = *formatp;
+       const char *percent = strchrnul(format, '%');
+
+       strbuf_add(sb, format, percent - format);
+       if (!*percent)
+               return 0;
+       *formatp = percent + 1;
+       return 1;
+}
+
 void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn,
                   void *context)
 {
-       for (;;) {
-               const char *percent;
+       while (strbuf_expand_step(sb, &format)) {
                size_t consumed;
 
-               percent = strchrnul(format, '%');
-               strbuf_add(sb, format, percent - format);
-               if (!*percent)
-                       break;
-               format = percent + 1;
-
                if (*format == '%') {
                        strbuf_addch(sb, '%');
                        format++;
@@ -1022,12 +1027,7 @@ void strbuf_addftime(struct strbuf *sb, const char *fmt, const struct tm *tm,
         * we want for %z, but the computation for %s has to convert to number
         * of seconds.
         */
-       for (;;) {
-               const char *percent = strchrnul(fmt, '%');
-               strbuf_add(&munged_fmt, fmt, percent - fmt);
-               if (!*percent)
-                       break;
-               fmt = percent + 1;
+       while (strbuf_expand_step(&munged_fmt, &fmt)) {
                switch (*fmt) {
                case '%':
                        strbuf_addstr(&munged_fmt, "%%");

diff --git a/strbuf.h b/strbuf.h
index 3dfeadb44c2e93e3e47cd448eaf8fd9133ac47bc..a189f12b84e6f427493cef675c66945b7532f6c5 100644 (file)
--- a/strbuf.h
+++ b/strbuf.h
@@ -371,6 +371,14 @@ size_t strbuf_expand_dict_cb(struct strbuf *sb,
                             const char *placeholder,
                             void *context);
 
+/**
+ * If the string pointed to by `formatp` contains a percent sign ("%"),
+ * advance it to point to the character following the next one and
+ * return 1, otherwise return 0.  Append the substring before that
+ * percent sign to `sb`, or the whole string if there is none.
+ */
+int strbuf_expand_step(struct strbuf *sb, const char **formatp);
+
 /**
  * Append the contents of one strbuf to another, quoting any
  * percent signs ("%") into double-percents ("%%") in the