[PATCH 2/4] help.c: make term_columns() cached and export it

From

Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>

Date

Feb 9, 2012, 23:58 UTC

Message-ID

<1328831921-27272-3-git-send-email-zbyszek@in.waw.pl>

In-Reply-To

<1328831921-27272-1-git-send-email-zbyszek@in.waw.pl>

Signed-off-by: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
---
 help.c  |   31 +++++++++++++++++++++++--------
 help.h  |    2 ++
 pager.c |    5 +++++
 3 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/help.c b/help.c
index bc15066..75b8d4b 100644
--- a/help.c
+++ b/help.c
@@ -5,26 +5,41 @@
 #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 (iff set) or $COLUMNS (iff 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");
-	int n_cols;
+	if (term_columns_cache)
+		return term_columns_cache;
 
-	if (col_string && (n_cols = atoi(col_string)) > 0)
-		return n_cols;
+	{
+		char *col_string = getenv("COLUMNS");
+		int n_cols;
+
+		if (col_string && (n_cols = atoi(col_string)) > 0)
+			return (term_columns_cache = n_cols);
+	}
 
 #ifdef TIOCGWINSZ
 	{
 		struct winsize ws;
 		if (!ioctl(1, TIOCGWINSZ, &ws)) {
 			if (ws.ws_col)
-				return ws.ws_col;
+				return (term_columns_cache = ws.ws_col);
 		}
 	}
 #endif
 
-	return 80;
+	return (term_columns_cache = 80);
 }
 
 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.rc2.127.gcb239