[PATCH][CLEANUP] remove ecb parameter from xdi_diff_outf()

[PATCH][CLEANUP] remove ecb parameter from xdi_diff_outf()

[René Scharfe]

xdi_diff_outf() overrides the structure members of its last parameter,
ignoring any value that callers pass in.  It's no surprise then that all
callers pass a pointer to an uninitialized structure.  They also don't
read it after the call, so the parameter is neither used for input nor
for output.   Turn it into a local variable of xdi_diff_outf().

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
---
 combine-diff.c    |    3 +--
 diff.c            |   15 +++++----------
 xdiff-interface.c |   11 ++++++-----
 xdiff-interface.h |    3 +--
 4 files changed, 13 insertions(+), 19 deletions(-)

diff --git a/combine-diff.c b/combine-diff.c
index 3480dae..7557136 100644
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -211,7 +211,6 @@ static void combine_diff(const unsigned char *parent, unsigned int mode,
 	xpparam_t xpp;
 	xdemitconf_t xecfg;
 	mmfile_t parent_file;
-	xdemitcb_t ecb;
 	struct combine_diff_state state;
 	unsigned long sz;
 
@@ -231,7 +230,7 @@ static void combine_diff(const unsigned char *parent, unsigned int mode,
 	state.n = n;
 
 	xdi_diff_outf(&parent_file, result_file, consume_line, &state,
-		      &xpp, &xecfg, &ecb);
+		      &xpp, &xecfg);
 	free(parent_file.ptr);
 
 	/* Assign line numbers for this parent.
diff --git a/diff.c b/diff.c
index d0ecbc3..e40c127 100644
--- a/diff.c
+++ b/diff.c
@@ -700,7 +700,6 @@ static void diff_words_show(struct diff_words_data *diff_words)
 {
 	xpparam_t xpp;
 	xdemitconf_t xecfg;
-	xdemitcb_t ecb;
 	mmfile_t minus, plus;
 
 	/* special case: only removal */
@@ -722,7 +721,7 @@ static void diff_words_show(struct diff_words_data *diff_words)
 	/* as only the hunk header will be parsed, we need a 0-context */
 	xecfg.ctxlen = 0;
 	xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
-		      &xpp, &xecfg, &ecb);
+		      &xpp, &xecfg);
 	free(minus.ptr);
 	free(plus.ptr);
 	if (diff_words->current_plus != diff_words->plus.text.ptr +
@@ -1708,7 +1707,6 @@ static void builtin_diff(const char *name_a,
 		const char *diffopts = getenv("GIT_DIFF_OPTS");
 		xpparam_t xpp;
 		xdemitconf_t xecfg;
-		xdemitcb_t ecb;
 		struct emit_callback ecbdata;
 		const struct userdiff_funcname *pe;
 
@@ -1780,7 +1778,7 @@ static void builtin_diff(const char *name_a,
 			}
 		}
 		xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
-			      &xpp, &xecfg, &ecb);
+			      &xpp, &xecfg);
 		if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS))
 			free_diff_words_data(&ecbdata);
 		if (textconv_one)
@@ -1833,13 +1831,12 @@ static void builtin_diffstat(const char *name_a, const char *name_b,
 		/* Crazy xdl interfaces.. */
 		xpparam_t xpp;
 		xdemitconf_t xecfg;
-		xdemitcb_t ecb;
 
 		memset(&xpp, 0, sizeof(xpp));
 		memset(&xecfg, 0, sizeof(xecfg));
 		xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
 		xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
-			      &xpp, &xecfg, &ecb);
+			      &xpp, &xecfg);
 	}
 
  free_and_return:
@@ -1881,14 +1878,13 @@ static void builtin_checkdiff(const char *name_a, const char *name_b,
 		/* Crazy xdl interfaces.. */
 		xpparam_t xpp;
 		xdemitconf_t xecfg;
-		xdemitcb_t ecb;
 
 		memset(&xpp, 0, sizeof(xpp));
 		memset(&xecfg, 0, sizeof(xecfg));
 		xecfg.ctxlen = 1; /* at least one context line */
 		xpp.flags = XDF_NEED_MINIMAL;
 		xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
-			      &xpp, &xecfg, &ecb);
+			      &xpp, &xecfg);
 
 		if (data.ws_rule & WS_BLANK_AT_EOF) {
 			struct emit_callback ecbdata;
@@ -3383,7 +3379,6 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
 	for (i = 0; i < q->nr; i++) {
 		xpparam_t xpp;
 		xdemitconf_t xecfg;
-		xdemitcb_t ecb;
 		mmfile_t mf1, mf2;
 		struct diff_filepair *p = q->queue[i];
 		int len1, len2;
@@ -3445,7 +3440,7 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
 		xecfg.ctxlen = 3;
 		xecfg.flags = XDL_EMIT_FUNCNAMES;
 		xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
-			      &xpp, &xecfg, &ecb);
+			      &xpp, &xecfg);
 	}
 
 	git_SHA1_Final(sha1, &ctx);
diff --git a/xdiff-interface.c b/xdiff-interface.c
index ca5e3fb..cd2285d 100644
--- a/xdiff-interface.c
+++ b/xdiff-interface.c
@@ -138,19 +138,20 @@ int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t co
 
 int xdi_diff_outf(mmfile_t *mf1, mmfile_t *mf2,
 		  xdiff_emit_consume_fn fn, void *consume_callback_data,
-		  xpparam_t const *xpp,
-		  xdemitconf_t const *xecfg, xdemitcb_t *xecb)
+		  xpparam_t const *xpp, xdemitconf_t const *xecfg)
 {
 	int ret;
 	struct xdiff_emit_state state;
+	xdemitcb_t ecb;
 
 	memset(&state, 0, sizeof(state));
 	state.consume = fn;
 	state.consume_callback_data = consume_callback_data;
-	xecb->outf = xdiff_outf;
-	xecb->priv = &state;
+	memset(&ecb, 0, sizeof(ecb));
+	ecb.outf = xdiff_outf;
+	ecb.priv = &state;
 	strbuf_init(&state.remainder, 0);
-	ret = xdi_diff(mf1, mf2, xpp, xecfg, xecb);
+	ret = xdi_diff(mf1, mf2, xpp, xecfg, &ecb);
 	strbuf_release(&state.remainder);
 	return ret;
 }
diff --git a/xdiff-interface.h b/xdiff-interface.h
index abba70c..49d1116 100644
--- a/xdiff-interface.h
+++ b/xdiff-interface.h
@@ -9,8 +9,7 @@ typedef void (*xdiff_emit_hunk_consume_fn)(void *, long, long, long);
 int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t const *xecfg, xdemitcb_t *ecb);
 int xdi_diff_outf(mmfile_t *mf1, mmfile_t *mf2,
 		  xdiff_emit_consume_fn fn, void *consume_callback_data,
-		  xpparam_t const *xpp,
-		  xdemitconf_t const *xecfg, xdemitcb_t *xecb);
+		  xpparam_t const *xpp, xdemitconf_t const *xecfg);
 int xdi_diff_hunks(mmfile_t *mf1, mmfile_t *mf2,
 		   xdiff_emit_hunk_consume_fn fn, void *consume_callback_data,
 		   xpparam_t const *xpp, xdemitconf_t *xecfg);
-- 
1.7.1

Re: [PATCH][CLEANUP] remove ecb parameter from xdi_diff_outf()

[Jeff King]

On Tue, May 04, 2010 at 10:41:34PM +0200, René Scharfe wrote:

> xdi_diff_outf() overrides the structure members of its last parameter,
> ignoring any value that callers pass in.  It's no surprise then that all
> callers pass a pointer to an uninitialized structure.  They also don't
> read it after the call, so the parameter is neither used for input nor
> for output.   Turn it into a local variable of xdi_diff_outf().

Heh:

  http://article.gmane.org/gmane.comp.version-control.git/102861

So,

Acked-by: Jeff King <peff@peff.net>

-Peff