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[PATCH 13/14] Avoid a dup2(2) in apply_filter() - start_command() can do it for us.

From
Johannes Sixt <johannes.sixt@telecom.at>
Date
Oct 19, 2007, 19:48 UTC
Message-ID
<1192823286-9654-14-git-send-email-johannes.sixt@telecom.at>
In-Reply-To
<1192823286-9654-13-git-send-email-johannes.sixt@telecom.at>

When apply_filter() runs the external (clean or smudge) filter program, it needs to pass the writable end of a pipe as its stdout. For this purpose, it used to dup2(2) the file descriptor explicitly to stdout. Now we use the facilities of start_command() to do it for us.

Furthermore, the path argument of a subordinate function, filter_buffer(), was not used, so here we replace it to pass the fd instead.

Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>
---
 convert.c |    7 +++----
 1 files changed, 3 insertions(+), 4 deletions(-)
diff --git a/convert.c b/convert.c
index d83c2fc..8dc9965 100644
--- a/convert.c
+++ b/convert.c
@@ -192,7 +192,7 @@ static int crlf_to_worktree(const char *path, const char *src, size_t len,
 	return 1;
 }
 
-static int filter_buffer(const char *path, const char *src,
+static int filter_buffer(int fd, const char *src,
 			 unsigned long size, const char *cmd)
 {
 	/*
@@ -205,6 +205,7 @@ static int filter_buffer(const char *path, const char *src,
 	memset(&child_process, 0, sizeof(child_process));
 	child_process.argv = argv;
 	child_process.in = -1;
+	child_process.out = fd;
 
 	if (start_command(&child_process))
 		return error("cannot fork to run external filter %s", cmd);
@@ -254,10 +255,8 @@ static int apply_filter(const char *path, const char *src, size_t len,
 		return 0;
 	}
 	if (!child_process.pid) {
-		dup2(pipe_feed[1], 1);
 		close(pipe_feed[0]);
-		close(pipe_feed[1]);
-		exit(filter_buffer(path, src, len, cmd));
+		exit(filter_buffer(pipe_feed[1], src, len, cmd));
 	}
 	close(pipe_feed[1]);
 
-- 
1.5.3.4.315.g2ce38
Previous: Johannes SixtNext: Johannes Sixt
Message 14 of 18 in “fork/exec removal series”
  1. 0/14 fork/exec removal seriesJohannes Sixt, Oct 19, 2007
  2. 01/14 Change git_connect() to return a struct child_process instead of a pid_t.Johannes Sixt, Oct 19, 2007
  3. 02/14 Use start_command() in git_connect() instead of explicit fork/exec.Johannes Sixt, Oct 19, 2007
  4. 03/14 Use start_command() to run content filters instead of explicit fork/exec.Johannes Sixt, Oct 19, 2007
  5. 04/14 Use run_command() to spawn external diff programs instead of fork/exec.Johannes Sixt, Oct 19, 2007
  6. 05/14 Use start_comand() in builtin-fetch-pack.c instead of explicit fork/exec.Johannes Sixt, Oct 19, 2007
  7. 06/14 Have start_command() create a pipe to read the stderr of the child.Johannes Sixt, Oct 19, 2007
  8. 07/14 upload-pack: Use start_command() to run pack-objects in create_pack_file().Johannes Sixt, Oct 19, 2007
  9. 08/14 Add infrastructure to run a function asynchronously.Johannes Sixt, Oct 19, 2007
  10. 09/14 Use the asyncronous function infrastructure in builtin-fetch-pack.c.Johannes Sixt, Oct 19, 2007
  11. 10/14 upload-pack: Move the revision walker into a separate function.Johannes Sixt, Oct 19, 2007
  12. 11/14 upload-pack: Run rev-list in an asynchronous function.Johannes Sixt, Oct 19, 2007
  13. 12/14 t0021-conversion.sh: Test that the clean filter really cleans content.Johannes Sixt, Oct 19, 2007
  14. 13/14 Avoid a dup2(2) in apply_filter() - start_command() can do it for us.Johannes Sixt, Oct 19, 2007
  15. 14/14 Use the asyncronous function infrastructure to run the content filter.Johannes Sixt, Oct 19, 2007
  16. Shawn O. PearceOct 20, 2007
  17. Johannes SixtOct 20, 2007
  18. Shawn O. PearceOct 21, 2007

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