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From: "Zbigniew Jędrzejewski-Szmek" <zbyszek@in.waw.pl>
To: git@vger.kernel.org, gitster@pobox.com, pclouds@gmail.com
Cc: "Michael J Gruber" <git@drmicha.warpmail.net>,
	"Zbigniew Jędrzejewski-Szmek" <zbyszek@in.waw.pl>
Subject: [PATCH 2/3] help.c: make term_columns() cached and export it
Date: Fri, 10 Feb 2012 17:39:31 +0100	[thread overview]
Message-ID: <1328891972-23695-3-git-send-email-zbyszek@in.waw.pl> (raw)
In-Reply-To: <1328891972-23695-1-git-send-email-zbyszek@in.waw.pl>

Since term_columns() will usually fail, when a pager is installed,
the cache is primed before the pager is installed. If a pager is not
installed, then the cache will be set on first use.

Conforms to The Single UNIX Specification, Version 2
(http://pubs.opengroup.org/onlinepubs/7908799/xbd/envvar.html#tag_002_003).

Signed-off-by: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
---
 help.c  |   37 +++++++++++++++++++++++++++++--------
 help.h  |    2 ++
 pager.c |    5 +++++
 3 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/help.c b/help.c
index bc15066..5d1cb1d 100644
--- a/help.c
+++ b/help.c
@@ -5,26 +5,47 @@
 #include "help.h"
 #include "common-cmds.h"
 
-/* most GUI terminals set COLUMNS (although some don't export it) */
-static int term_columns(void)
+/* 
+ * Cache for term_columns() value. Set on first use or when
+ * installing a pager and replacing stdout.
+ */
+static int term_columns_cache;
+
+/* 
+ * Return cached value (if set) or $COLUMNS (if set and positive) or
+ * ioctl(1, TIOCGWINSZ).ws_col (if positive) or 80.
+ *
+ * $COLUMNS even if set, is usually not exported, so
+ * the variable can be used to override autodection.
+ */
+int term_columns(void)
 {
-	char *col_string = getenv("COLUMNS");
+	char *col_string;
 	int n_cols;
 
-	if (col_string && (n_cols = atoi(col_string)) > 0)
-		return n_cols;
+	if (term_columns_cache)
+		return term_columns_cache;
+
+	col_string = getenv("COLUMNS");
+	if (col_string && (n_cols = atoi(col_string)) > 0) {
+		term_columns_cache = n_cols;
+		return term_columns_cache;
+	}
 
 #ifdef TIOCGWINSZ
 	{
 		struct winsize ws;
 		if (!ioctl(1, TIOCGWINSZ, &ws)) {
-			if (ws.ws_col)
-				return ws.ws_col;
+			if (ws.ws_col) {
+				term_columns_cache = ws.ws_col;
+				return term_columns_cache;
+			}
 		}
 	}
 #endif
 
-	return 80;
+	term_columns_cache = 80;
+	return term_columns_cache;
 }
 
 void add_cmdname(struct cmdnames *cmds, const char *name, int len)
diff --git a/help.h b/help.h
index b6b12d5..880a4b4 100644
--- a/help.h
+++ b/help.h
@@ -29,4 +29,6 @@ extern void list_commands(const char *title,
 			  struct cmdnames *main_cmds,
 			  struct cmdnames *other_cmds);
 
+extern int term_columns(void);
+
 #endif /* HELP_H */
diff --git a/pager.c b/pager.c
index 975955b..e7032de 100644
--- a/pager.c
+++ b/pager.c
@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "run-command.h"
 #include "sigchain.h"
+#include "help.h"
 
 #ifndef DEFAULT_PAGER
 #define DEFAULT_PAGER "less"
@@ -76,6 +77,10 @@ void setup_pager(void)
 	if (!pager)
 		return;
 
+	/* prime the term_columns() cache before it is too
+	 * late and stdout is replaced */
+	(void) term_columns();
+
 	setenv("GIT_PAGER_IN_USE", "true", 1);
 
 	/* spawn the pager */
-- 
1.7.9.263.g4be11.dirty

  parent reply	other threads:[~2012-02-10 16:40 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-09 23:58 (unknown), Zbigniew Jędrzejewski-Szmek
2012-02-09 23:58 ` [PATCH 1/4] Move git_version_string to help.c in preparation for diff changes Zbigniew Jędrzejewski-Szmek
2012-02-10  0:46   ` Junio C Hamano
2012-02-09 23:58 ` [PATCH 2/4] help.c: make term_columns() cached and export it Zbigniew Jędrzejewski-Szmek
2012-02-10  0:50   ` Junio C Hamano
2012-02-09 23:58 ` [PATCH 3/4] diff --stat: use the real terminal width Zbigniew Jędrzejewski-Szmek
2012-02-10  0:54   ` Junio C Hamano
2012-02-10  6:15   ` Nguyen Thai Ngoc Duy
2012-02-10 11:25     ` Zbigniew Jędrzejewski-Szmek
2012-02-10 13:00       ` Nguyen Thai Ngoc Duy
2012-02-10 16:39       ` [PATCH 0/3 v2] " Zbigniew Jędrzejewski-Szmek
2012-02-10 16:39         ` [PATCH 1/3] Move git_version_string to help.c before diff changes Zbigniew Jędrzejewski-Szmek
2012-02-10 17:58           ` Junio C Hamano
2012-02-10 16:39         ` Zbigniew Jędrzejewski-Szmek [this message]
2012-02-11  4:36           ` [PATCH 2/3] help.c: make term_columns() cached and export it Nguyen Thai Ngoc Duy
2012-02-11 10:49             ` Zbigniew Jędrzejewski-Szmek
2012-02-12  9:40               ` Junio C Hamano
2012-02-12 14:12                 ` [PATCH 1/2] Save terminal width before setting up pager and export term_columns() Zbigniew Jędrzejewski-Szmek
2012-02-13 23:00                   ` Junio C Hamano
2012-02-14 11:44                   ` Nguyen Thai Ngoc Duy
2012-02-14 11:53                     ` Zbigniew Jędrzejewski-Szmek
2012-02-12 14:16                 ` [PATCH 2/2] Rename lineno_width to decimal_width and export it Zbigniew Jędrzejewski-Szmek
2012-02-13 23:29                   ` Junio C Hamano
2012-02-14 12:24                     ` [PATCH v2] make lineno_width() from blame reusable for others Zbigniew Jędrzejewski-Szmek
2012-02-10 16:39         ` [PATCH 3/3] diff --stat: use the real terminal width Zbigniew Jędrzejewski-Szmek
2012-02-10 18:24         ` [PATCH 0/3 v2] " Junio C Hamano
2012-02-12 14:30           ` [PATCH v3] diff --stat: use the full " Zbigniew Jędrzejewski-Szmek
2012-02-14  1:08             ` Junio C Hamano
2012-02-14 23:45               ` [PATCH 1/3 v4] " Zbigniew Jędrzejewski-Szmek
2012-02-14 23:45                 ` [PATCH 2/3 v4] diff --stat: better alignment for binary files Zbigniew Jędrzejewski-Szmek
2012-02-14 23:45                 ` [PATCH 3/3 v4] Update diff --stat output in tests and tutorial Zbigniew Jędrzejewski-Szmek
2012-02-15  1:21                   ` Junio C Hamano
2012-02-15 11:03                     ` [PATCH 1/3 v5] diff --stat: tests for long filenames and big change counts Zbigniew Jędrzejewski-Szmek
2012-02-15 11:03                       ` [PATCH 2/3 v5] diff --stat: use the full terminal width Zbigniew Jędrzejewski-Szmek
2012-02-15 18:07                         ` Junio C Hamano
2012-02-15 11:03                       ` [PATCH 3/3 v5] diff --stat: use less columns for change counts Zbigniew Jędrzejewski-Szmek
2012-02-15 12:12                         ` Nguyen Thai Ngoc Duy
2012-02-15 17:12                       ` [PATCH 1/3 v5] diff --stat: tests for long filenames and big " Junio C Hamano
2012-02-15 17:33                         ` Junio C Hamano
2012-02-16  9:57                         ` Zbigniew Jędrzejewski-Szmek
2012-02-16 20:01                           ` Junio C Hamano
2012-02-15  0:07                 ` [PATCH 1/3 v4] diff --stat: use the full terminal width Junio C Hamano
2012-02-15  1:18                 ` Junio C Hamano
2012-02-15  7:39                 ` Johannes Sixt
2012-02-09 23:58 ` [PATCH 4/4] diff --stat: use most of the space for file names Zbigniew Jędrzejewski-Szmek
2012-02-10  0:55   ` Junio C Hamano

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