logmsg_reencode: return const buffer

The return value from logmsg_reencode may be either a newly
allocated buffer or a pointer to the existing commit->buffer.
We would not want the caller to accidentally free() or
modify the latter, so let's mark it as const.  We can cast
away the constness in logmsg_free, but only once we have
determined that it is a free-able buffer.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/blame.c b/builtin/blame.c
index 6e22bdfbfab9088bb58f67c3fc07dd819ed5bec5..85a36813069f91e3a9b8ea5aa172d015265b9385 100644 (file)
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -1405,7 +1405,7 @@ static void get_commit_info(struct commit *commit,
 {
        int len;
        const char *subject, *encoding;
-       char *message;
+       const char *message;
 
        commit_info_init(ret);
 

diff --git a/builtin/reset.c b/builtin/reset.c
index f4e087596b6337d2306af4cf45119752b4a049ea..b5312c4c6523ceba05bb2cf40b37fd740b0fbddf 100644 (file)
--- a/builtin/reset.c
+++ b/builtin/reset.c
@@ -93,7 +93,7 @@ static int reset_index(const unsigned char *sha1, int reset_type, int quiet)
 static void print_new_head_line(struct commit *commit)
 {
        const char *hex, *body;
-       char *msg;
+       const char *msg;
 
        hex = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
        printf(_("HEAD is now at %s"), hex);

diff --git a/commit.h b/commit.h
index 1cb55ae63dad95ac0650a8b386bb5e2cb6056ffa..4df48cb68819bd914cfa7d087034775eba3a4c93 100644 (file)
--- a/commit.h
+++ b/commit.h
@@ -115,10 +115,10 @@ struct userformat_want {
 
 extern int has_non_ascii(const char *text);
 struct rev_info; /* in revision.h, it circularly uses enum cmit_fmt */
-extern char *logmsg_reencode(const struct commit *commit,
-                            char **commit_encoding,
-                            const char *output_encoding);
-extern void logmsg_free(char *msg, const struct commit *commit);
+extern const char *logmsg_reencode(const struct commit *commit,
+                                  char **commit_encoding,
+                                  const char *output_encoding);
+extern void logmsg_free(const char *msg, const struct commit *commit);
 extern void get_commit_format(const char *arg, struct rev_info *);
 extern const char *format_subject(struct strbuf *sb, const char *msg,
                                  const char *line_separator);

diff --git a/pretty.c b/pretty.c
index 3c43db558aee43b0ea69c23c6611dcc9fae0661f..85b0bb3431271638a6c717dbe9174017abc5cfb1 100644 (file)
--- a/pretty.c
+++ b/pretty.c
@@ -606,9 +606,9 @@ static char *replace_encoding_header(char *buf, const char *encoding)
        return strbuf_detach(&tmp, NULL);
 }
 
-char *logmsg_reencode(const struct commit *commit,
-                     char **commit_encoding,
-                     const char *output_encoding)
+const char *logmsg_reencode(const struct commit *commit,
+                           char **commit_encoding,
+                           const char *output_encoding)
 {
        static const char *utf8 = "UTF-8";
        const char *use_encoding;
@@ -687,10 +687,10 @@ char *logmsg_reencode(const struct commit *commit,
        return out ? out : msg;
 }
 
-void logmsg_free(char *msg, const struct commit *commit)
+void logmsg_free(const char *msg, const struct commit *commit)
 {
        if (msg != commit->buffer)
-               free(msg);
+               free((void *)msg);
 }
 
 static int mailmap_name(const char **email, size_t *email_len,
@@ -796,7 +796,7 @@ struct format_commit_context {
        struct signature_check signature_check;
        enum flush_type flush_type;
        enum trunc_type truncate;
-       char *message;
+       const char *message;
        char *commit_encoding;
        size_t width, indent1, indent2;
        int auto_color;
@@ -1700,7 +1700,7 @@ void pretty_print_commit(struct pretty_print_context *pp,
        unsigned long beginning_of_body;
        int indent = 4;
        const char *msg;
-       char *reencoded;
+       const char *reencoded;
        const char *encoding;
        int need_8bit_cte = pp->need_8bit_cte;
 

diff --git a/revision.c b/revision.c
index 71e233742331a435edeadacc7c6a52226bb18b7a..be151ef46206757994dfd1f2976677247f7d730f 100644 (file)
--- a/revision.c
+++ b/revision.c
@@ -2788,7 +2788,7 @@ static int commit_match(struct commit *commit, struct rev_info *opt)
 {
        int retval;
        const char *encoding;
-       char *message;
+       const char *message;
        struct strbuf buf = STRBUF_INIT;
 
        if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
@@ -2830,12 +2830,19 @@ static int commit_match(struct commit *commit, struct rev_info *opt)
                format_display_notes(commit->object.sha1, &buf, encoding, 1);
        }
 
-       /* Find either in the original commit message, or in the temporary */
+       /*
+        * Find either in the original commit message, or in the temporary.
+        * Note that we cast away the constness of "message" here. It is
+        * const because it may come from the cached commit buffer. That's OK,
+        * because we know that it is modifiable heap memory, and that while
+        * grep_buffer may modify it for speed, it will restore any
+        * changes before returning.
+        */
        if (buf.len)
                retval = grep_buffer(&opt->grep_filter, buf.buf, buf.len);
        else
                retval = grep_buffer(&opt->grep_filter,
-                                    message, strlen(message));
+                                    (char *)message, strlen(message));
        strbuf_release(&buf);
        logmsg_free(message, commit);
        return retval;