strbuf change: be sure ->buf is never ever NULL.

For that purpose, the ->buf is always initialized with a char * buf living
in the strbuf module. It is made a char * so that we can sloppily accept
things that perform: sb->buf[0] = '\0', and because you can't pass "" as an
initializer for ->buf without making gcc unhappy for very good reasons.

strbuf_init/_detach/_grow have been fixed to trust ->alloc and not ->buf
anymore.

as a consequence strbuf_detach is _mandatory_ to detach a buffer, copying
->buf isn't an option anymore, if ->buf is going to escape from the scope,
and eventually be free'd.

API changes:
  * strbuf_setlen now always works, so just make strbuf_reset a convenience
    macro.
  * strbuf_detatch takes a size_t* optional argument (meaning it can be
    NULL) to copy the buffer's len, as it was needed for this refactor to
    make the code more readable, and working like the callers.

Signed-off-by: Pierre Habouzit <madcoder@debian.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 7 insertions, 9 deletions

diff --git a/builtin-apply.c b/builtin-apply.c
index 01c9d6064..740623e6c 100644
--- a/builtin-apply.c
+++ b/builtin-apply.c
@@ -178,14 +178,13 @@ static void say_patch_name(FILE *output, const char *pre, struct patch *patch, c
 #define CHUNKSIZE (8192)
 #define SLOP (16)
 
-static void *read_patch_file(int fd, unsigned long *sizep)
+static void *read_patch_file(int fd, size_t *sizep)
 {
 	struct strbuf buf;
 
 	strbuf_init(&buf, 0);
 	if (strbuf_read(&buf, fd, 0) < 0)
 		die("git-apply: read returned %s", strerror(errno));
-	*sizep = buf.len;
 
 	/*
 	 * Make sure that we have some slop in the buffer
@@ -194,7 +193,7 @@ static void *read_patch_file(int fd, unsigned long *sizep)
 	 */
 	strbuf_grow(&buf, SLOP);
 	memset(buf.buf + buf.len, 0, SLOP);
-	return strbuf_detach(&buf);
+	return strbuf_detach(&buf, sizep);
 }
 
 static unsigned long linelen(const char *buffer, unsigned long size)
@@ -253,7 +252,7 @@ static char *find_name(const char *line, char *def, int p_value, int terminate)
 				 */
 				strbuf_remove(&name, 0, cp - name.buf);
 				free(def);
-				return name.buf;
+				return strbuf_detach(&name, NULL);
 			}
 		}
 		strbuf_release(&name);
@@ -607,7 +606,7 @@ static char *git_header_name(char *line, int llen)
 			if (strcmp(cp + 1, first.buf))
 				goto free_and_fail1;
 			strbuf_release(&sp);
-			return first.buf;
+			return strbuf_detach(&first, NULL);
 		}
 
 		/* unquoted second */
@@ -618,7 +617,7 @@ static char *git_header_name(char *line, int llen)
 		if (line + llen - cp != first.len + 1 ||
 		    memcmp(first.buf, cp, first.len))
 			goto free_and_fail1;
-		return first.buf;
+		return strbuf_detach(&first, NULL);
 
 	free_and_fail1:
 		strbuf_release(&first);
@@ -655,7 +654,7 @@ static char *git_header_name(char *line, int llen)
 			    isspace(name[len])) {
 				/* Good */
 				strbuf_remove(&sp, 0, np - sp.buf);
-				return sp.buf;
+				return strbuf_detach(&sp, NULL);
 			}
 
 		free_and_fail2:
@@ -1968,8 +1967,7 @@ static int apply_data(struct patch *patch, struct stat *st, struct cache_entry *
 
 	if (apply_fragments(&buf, patch) < 0)
 		return -1; /* note with --reject this succeeds. */
-	patch->result = buf.buf;
-	patch->resultsize = buf.len;
+	patch->result = strbuf_detach(&buf, &patch->resultsize);
 
 	if (0 < patch->is_delete && patch->resultsize)
 		return error("removal patch leaves file contents");