Re: [PATCH 2/3] help.c: make term_columns() cached and export it

@@ -1175,6 +1175,7 @@ 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;

@@ -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);

@@ -76,6 +76,10 @@ 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 */

@@ -110,3 +114,44 @@ 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 (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)
+{
+	static int term_columns_cache;
+
+	char *col_string;
+	int 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) {
+				term_columns_cache = ws.ws_col;
+				return term_columns_cache;
+			}
+		}
+	}
+#endif
+
+	term_columns_cache = 80;
+	return term_columns_cache;
+}

@@ -1829,18 +1829,6 @@ static int read_ancestry(const char *graft_file)
 }
 
 /*
- * How many columns do we need to show line numbers in decimal?
- */
-static int lineno_width(int lines)
-{
-	int i, width;
-
-	for (width = 1, i = 10; i <= lines; width++)
-		i *= 10;
-	return width;
-}
-
-/*
  * How many columns do we need to show line numbers, authors,
  * and filenames?
  */

@@ -1880,9 +1868,9 @@ static void find_alignment(struct scoreboard *sb, int *option)
 		if (largest_score < ent_score(sb, e))
 			largest_score = ent_score(sb, e);
 	}
-	max_orig_digits = lineno_width(longest_src_lines);
-	max_digits = lineno_width(longest_dst_lines);
-	max_score_digits = lineno_width(largest_score);
+	max_orig_digits = decimal_width(longest_src_lines);
+	max_digits = decimal_width(longest_dst_lines);
+	max_score_digits = decimal_width(largest_score);
 }
 
 /*

@@ -1176,6 +1176,7 @@ extern const char *pager_program;
 extern int pager_in_use(void);
 extern int pager_use_color;
 extern int term_columns(void);
+extern int decimal_width(int number);
 
 extern const char *editor_program;
 extern const char *askpass_program;

@@ -155,3 +155,15 @@ int term_columns(void)
 	term_columns_cache = 80;
 	return term_columns_cache;
 }
+
+/*
+ * How many columns do we need to show numbers in decimal?
+ */
+int decimal_width(int number)
+{
+	int i, width;
+
+	for (width = 1, i = 10; i <= number; width++)
+		i *= 10;
+	return width;
+}

@@ -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;

@@ -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);

@@ -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 +116,40 @@ 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 (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)
+{
+	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)) {
+			if (ws.ws_col) {
+				term_columns_at_startup = ws.ws_col;
+			}
+		}
+	}
+#endif
+	return term_columns_at_startup;
+}