From: "Zbigniew Jędrzejewski-Szmek" <zbyszek@in.waw.pl>
To: Nguyen Thai Ngoc Duy <pclouds@gmail.com>
Cc: git@vger.kernel.org, gitster@pobox.com,
Michael J Gruber <git@drmicha.warpmail.net>,
Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Subject: Re: [PATCH 2/3] help.c: make term_columns() cached and export it
Date: Sat, 11 Feb 2012 11:49:24 +0100 [thread overview]
Message-ID: <4F3647B4.8090803@in.waw.pl> (raw)
In-Reply-To: <CACsJy8AjqqEpJr64DJUqVumw1sB2g3pvuz-g4DxhmS-ZbGhY3w@mail.gmail.com>
On 02/11/2012 05:36 AM, Nguyen Thai Ngoc Duy wrote:
> 2012/2/10 Zbigniew Jędrzejewski-Szmek<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.
>
> Conflict alert. term_columns() is also moved out of help.c in
> nd/columns series on pu, commit cb0850f (Save terminal width before
> setting up pager - 2012-02-04)
Thanks for the heads-up. I think that the two patches should be
merged, especially because there's an error in cb0850f (a variable is
read-only, never written).
Tweaks to cb0850f (Save terminal width before setting up pager -
2012-02-04):
[This actually was done on top of today's pu, so it will not apply
cleanly to cb0850f].
- term_columns() lives in pager.c so it should be declared in
cache.h like other public functions in pager.c. It has nothing to do
with columns.h.
- simplify logic to use a static variable instead of two global
variables (cb0850f actually doesn't work at all because
spawned_pager wasn't ever set).
- check the cache first, then do getenv(COLUMNS) + atoi, then do
ioctl(). The behaviour is equivalent to checking COLUMNS first, but
is slightly more efficient.
- document the function
- remove #include "column.h" added in 88c9754c4097 column: Fix some
compiler and sparse warnings (Wed Feb 8 2012).
Junio suggested that "a new file, term.c or something, be a lot more
suitable home for the function you will be reusing from diff and other
parts of the system". Nevertheless, I think that adding two files (.c
and .h) to hold one function isn't worth it. It can live in pager.c.
Terminal size is logically connected to paging after all.
---
cache.h | 1 +
column.h | 1 -
pager.c | 64 +++++++++++++++++++++++-----------------
3 files changed, 38 insertions(+), 28 deletions(-)
diff --git a/cache.h b/cache.h
index 6c70dbc..b4422d4 100644
--- a/cache.h
+++ b/cache.h
@@ -1196,6 +1196,7 @@ 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/column.h b/column.h
index b9dec64..142299e 100644
--- a/column.h
+++ b/column.h
@@ -17,7 +17,6 @@ struct column_options {
const char *nl;
};
-extern int term_columns(void);
extern void print_columns(const struct string_list *list,
unsigned int mode,
struct column_options *opts);
diff --git a/pager.c b/pager.c
index fe203a7..d105761 100644
--- a/pager.c
+++ b/pager.c
@@ -7,21 +7,6 @@
#define DEFAULT_PAGER "less"
#endif
-static int spawned_pager;
-static int max_columns;
-
-static int retrieve_terminal_width(void)
-{
-#ifdef TIOCGWINSZ
- struct winsize ws;
- if (ioctl(1, TIOCGWINSZ, &ws)) /* e.g., ENOSYS */
- return 0;
- return ws.ws_col;
-#else
- return 0;
-#endif
-}
-
/*
* This is split up from the rest of git so that we can do
* something different on Windows.
@@ -88,16 +73,15 @@ const char *git_pager(int stdout_is_tty)
void setup_pager(void)
{
const char *pager = git_pager(isatty(1));
- int width;
if (!pager || pager_in_use())
return;
- setenv("GIT_PAGER_IN_USE", "true", 1);
+ /* prime the term_columns() cache before it is too
+ * late and stdout is replaced */
+ (void) term_columns();
- width = retrieve_terminal_width();
- if (width)
- max_columns = width;
+ setenv("GIT_PAGER_IN_USE", "true", 1);
/* spawn the pager */
pager_argv[0] = pager;
@@ -132,17 +116,43 @@ int pager_in_use(void)
return env ? git_config_bool("GIT_PAGER_IN_USE", env) : 0;
}
+/*
+ * 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.
+ * This behaviour conforms to The Single UNIX Specification, Version 2
+ *
(http://pubs.opengroup.org/onlinepubs/7908799/xbd/envvar.html#tag_002_003).
+ */
int term_columns(void)
{
- char *col_string = getenv("COLUMNS");
+ static int term_columns_cache;
+
+ 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;
+ }
- if (spawned_pager && max_columns)
- return max_columns;
+#ifdef TIOCGWINSZ
+ {
+ struct winsize ws;
+ if (!ioctl(1, TIOCGWINSZ, &ws)) {
+ if (ws.ws_col) {
+ term_columns_cache = ws.ws_col;
+ return term_columns_cache;
+ }
+ }
+ }
+#endif
- n_cols = retrieve_terminal_width();
- return n_cols ? n_cols : 80;
+ term_columns_cache = 80;
+ return term_columns_cache;
}
--
1.7.9.310.g883d84c.dirty
next prev parent reply other threads:[~2012-02-11 10:50 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 ` [PATCH 2/3] help.c: make term_columns() cached and export it Zbigniew Jędrzejewski-Szmek
2012-02-11 4:36 ` Nguyen Thai Ngoc Duy
2012-02-11 10:49 ` Zbigniew Jędrzejewski-Szmek [this message]
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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