pager: find out the terminal width before spawning the pager

term_columns() checks for terminal width via ioctl(2) on the standard
output, but we spawn the pager too early for this check to be useful.

The effect of this buglet can be observed by opening a wide terminal and
running "git -p help --all", which still shows 80-column output, while
"git help --all" uses the full terminal width. Run the check before we
spawn the pager to fix this.

While at it, move term_columns() to pager.c and export it from cache.h so
that callers other than the help subsystem can use it.

Signed-off-by: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/cache.h b/cache.h
index 79c612fc2f51a5adf059a7a9ec2b8e7882388faa..c7e3b4d49e64ef05b4f094f46fec06ded5704907 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -1172,6 +1172,7 @@ extern void setup_pager(void);
 extern const char *pager_program;
 extern int pager_in_use(void);
 extern int pager_use_color;
+extern int term_columns(void);
 
 extern const char *editor_program;
 extern const char *askpass_program;

diff --git a/help.c b/help.c
index cbbe966f685b276cac702bb0fd9a44bfbf5f0e79..14eefc91ced3890975d0833ffc83971c7986858b 100644 (file)
--- a/help.c
+++ b/help.c
@@ -5,28 +5,6 @@
 #include "help.h"
 #include "common-cmds.h"
 
-/* most GUI terminals set COLUMNS (although some don't export it) */
-static int term_columns(void)
-{
-       char *col_string = getenv("COLUMNS");
-       int n_cols;
-
-       if (col_string && (n_cols = atoi(col_string)) > 0)
-               return n_cols;
-
-#ifdef TIOCGWINSZ
-       {
-               struct winsize ws;
-               if (!ioctl(1, TIOCGWINSZ, &ws)) {
-                       if (ws.ws_col)
-                               return ws.ws_col;
-               }
-       }
-#endif
-
-       return 80;
-}
-
 void add_cmdname(struct cmdnames *cmds, const char *name, int len)
 {
        struct cmdname *ent = xmalloc(sizeof(*ent) + len + 1);

diff --git a/pager.c b/pager.c
index 975955ba82a0dbb128d6733090cd74c2b509ea81..b7909678f459d90d1c8907c78bb5fcb512fe558d 100644 (file)
--- a/pager.c
+++ b/pager.c
@@ -76,6 +76,12 @@ void setup_pager(void)
        if (!pager)
                return;
 
+       /*
+        * force computing the width of the terminal before we redirect
+        * the standard output to the pager.
+        */
+       (void) term_columns();
+
        setenv("GIT_PAGER_IN_USE", "true", 1);
 
        /* spawn the pager */
@@ -110,3 +116,34 @@ int pager_in_use(void)
        env = getenv("GIT_PAGER_IN_USE");
        return env ? git_config_bool("GIT_PAGER_IN_USE", env) : 0;
 }
+
+/*
+ * Return cached value (if set) or $COLUMNS environment variable (if
+ * set and positive) or ioctl(1, TIOCGWINSZ).ws_col (if positive),
+ * and default to 80 if all else fails.
+ */
+int term_columns(void)
+{
+       static int term_columns_at_startup;
+
+       char *col_string;
+       int n_cols;
+
+       if (term_columns_at_startup)
+               return term_columns_at_startup;
+
+       term_columns_at_startup = 80;
+
+       col_string = getenv("COLUMNS");
+       if (col_string && (n_cols = atoi(col_string)) > 0)
+               term_columns_at_startup = n_cols;
+#ifdef TIOCGWINSZ
+       else {
+               struct winsize ws;
+               if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col)
+                       term_columns_at_startup = ws.ws_col;
+       }
+#endif
+
+       return term_columns_at_startup;
+}