Merge branches zj/decimal-width, zj/term-columns and jc/diff-stat-scaler

cache.h

@@ -1176,6 +1176,7 @@ 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 int decimal_width(int);
 
 extern const char *editor_program;

diff.c

@@ -1276,13 +1276,15 @@ const char mime_boundary_leader[] = "------------";
 
 static int scale_linear(int it, int width, int max_change)
 {
+	if (!it)
+		return 0;
 	/*
-	 * make sure that at least one '-' is printed if there were deletions,
-	 * and likewise for '+'.
+	 * make sure that at least one '-' or '+' is printed if
+	 * there is any change to this path. The easiest way is to
+	 * scale linearly as if the alloted width is one column shorter
+	 * than it is, and then add 1 to the result.
 	 */
-	if (max_change < 2)
-		return it;
-	return ((it - 1) * (width - 1) + max_change - 1) / (max_change - 1);
+	return 1 + (it * (width - 1) / max_change);
 }
 
 static void show_name(FILE *file,
@@ -1449,8 +1451,19 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 		dels += del;
 
 		if (width <= max_change) {
+			int total = add + del;
+
+			total = scale_linear(add + del, width, max_change);
+			if (total < 2 && add && del)
+				/* width >= 2 due to the sanity check */
+				total = 2;
+			if (add < del) {
 				add = scale_linear(add, width, max_change);
+				del = total - add;
+			} else {
 				del = scale_linear(del, width, max_change);
+				add = total - del;
+			}
 		}
 		fprintf(options->file, "%s", line_prefix);
 		show_name(options->file, prefix, name, len);

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);

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 */
@@ -111,6 +117,37 @@ int pager_in_use(void)
 	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;
+}
+
 /*
  * How many columns do we need to show this number in decimal?
  */