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[PATCHv3 08/16] bash prompt: use bash builtins to find out rebase state

From
SZEDER Gábor <szeder@ira.uka.de>
Date
Jun 24, 2013, 16:39 UTC
Message-ID
<1372091966-19315-9-git-send-email-szeder@ira.uka.de>
In-Reply-To
<1372091966-19315-1-git-send-email-szeder@ira.uka.de>

During an ongoing interactive rebase __git_ps1() finds out the name of the rebased branch, the total number of patches and the number of the current patch by executing a '$(cat .git/rebase-merge/<FILE>)' command substitution for each. That is not quite the most efficient way to read single line single word files, because it imposes the overhead of fork()ing a subshell and fork()+exec()ing 'cat' several times.

Use the 'read' bash builtin instead to avoid those overheads.
Signed-off-by: SZEDER Gábor <szeder@ira.uka.de>
---
 contrib/completion/git-prompt.sh | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/contrib/completion/git-prompt.sh b/contrib/completion/git-prompt.sh
index 0563dea8..bc402f56 100644
--- a/contrib/completion/git-prompt.sh
+++ b/contrib/completion/git-prompt.sh
@@ -325,9 +325,9 @@ __git_ps1 ()
 	local step=""
 	local total=""
 	if [ -d "$g/rebase-merge" ]; then
-		b="$(cat "$g/rebase-merge/head-name" 2>/dev/null)"
-		step=$(cat "$g/rebase-merge/msgnum" 2>/dev/null)
-		total=$(cat "$g/rebase-merge/end" 2>/dev/null)
+		read b 2>/dev/null <"$g/rebase-merge/head-name"
+		read step 2>/dev/null <"$g/rebase-merge/msgnum"
+		read total 2>/dev/null <"$g/rebase-merge/end"
 		if [ -f "$g/rebase-merge/interactive" ]; then
 			r="|REBASE-i"
 		else
@@ -335,10 +335,10 @@ __git_ps1 ()
 		fi
 	else
 		if [ -d "$g/rebase-apply" ]; then
-			step=$(cat "$g/rebase-apply/next" 2>/dev/null)
-			total=$(cat "$g/rebase-apply/last" 2>/dev/null)
+			read step 2>/dev/null <"$g/rebase-apply/next"
+			read total 2>/dev/null <"$g/rebase-apply/last"
 			if [ -f "$g/rebase-apply/rebasing" ]; then
-				b="$(cat "$g/rebase-apply/head-name" 2>/dev/null)"
+				read b 2>/dev/null <"$g/rebase-apply/head-name"
 				r="|REBASE"
 			elif [ -f "$g/rebase-apply/applying" ]; then
 				r="|AM"

-- 
1.8.3.1.599.g4459181
Previous: SZEDER GáborNext: SZEDER Gábor
Message 9 of 19 in “[PATCHv3 00/16] bash prompt speedup”
  1. SZEDER GáborJun 24, 2013
  2. 01/16 bash prompt: fix redirection coding style in testsSZEDER Gábor, Jun 24, 2013
  3. 02/16 bash prompt: use 'write_script' helper in interactive rebase testSZEDER Gábor, Jun 24, 2013
  4. 03/16 completion, bash prompt: move __gitdir() tests to completion test suiteSZEDER Gábor, Jun 24, 2013
  5. 04/16 bash prompt: add a test for symbolic link symbolic refsSZEDER Gábor, Jun 24, 2013
  6. 05/16 bash prompt: print unique detached HEAD abbreviated object nameSZEDER Gábor, Jun 24, 2013
  7. 06/16 bash prompt: return early from __git_ps1() when not in a git repositorySZEDER Gábor, Jun 24, 2013
  8. 07/16 bash prompt: run 'git rev-parse --git-dir' directly instead of __gitdir()SZEDER Gábor, Jun 24, 2013
  9. 08/16 bash prompt: use bash builtins to find out rebase stateSZEDER Gábor, Jun 24, 2013
  10. 09/16 bash prompt: use bash builtins to find out current branchSZEDER Gábor, Jun 24, 2013
  11. 10/16 bash prompt: combine 'git rev-parse' executions in the main code pathSZEDER Gábor, Jun 24, 2013
  12. 11/16 bash prompt: combine 'git rev-parse' for detached headSZEDER Gábor, Jun 24, 2013
  13. 12/16 bash prompt: use bash builtins to check for unborn branch for dirty stateSZEDER Gábor, Jun 24, 2013
  14. 13/16 bash prompt: use bash builtins to check stash stateSZEDER Gábor, Jun 24, 2013
  15. 14/16 bash prompt: avoid command substitution when checking for untracked filesSZEDER Gábor, Jun 24, 2013
  16. 15/16 bash prompt: avoid command substitution when finalizing gitstringSZEDER Gábor, Jun 24, 2013
  17. 16/16 bash prompt: mention that PROMPT_COMMAND mode is fasterSZEDER Gábor, Jun 24, 2013
  18. Junio C HamanoJun 24, 2013
  19. Eduardo R. D'AvilaJun 25, 2013

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