Reduce calls to getcols

This dramatically improves upon a much older attempt in 2008 in commit
ce3d70aa99ab86. We don't need to call it once per line we print unless
there is a reasonable expectation of being able to resize the terminal
mid-operation; this is really only the case during our callback progress
bars.

Some before and after numbers of ioctl() calls, gleaned from strace of
the following operations (no targets to any of them to maximize the
amount of output):

    pacman -Qii :  37768 ->  2616  (93.1% decrease)
    pacman -Qs  :   2616 ->     4  (99.8%)
    pacman -Sii : 133036 -> 10926  (91.8%)
    pacman -Ss  :  10926 ->    14  (99.9%)

Obviously the search results are astounding; we only call getcols()
once in the case of -Qs, and once per repo in the case of -Ss. For
-Qii and -Sii we are still calling it once per package, but this is
much better than once per line of info output.

Signed-off-by: Dan McGee <dan@archlinux.org>

1 files changed, 35 insertions, 28 deletions

diff --git a/src/pacman/util.c b/src/pacman/util.c
index 15cd6fd7..4b8684e2 100644
--- a/src/pacman/util.c
+++ b/src/pacman/util.c
@@ -254,12 +254,11 @@ char *mdirname(const char *path)
 
 /* output a string, but wrap words properly with a specified indentation
  */
-void indentprint(const char *str, size_t indent)
+void indentprint(const char *str, unsigned short indent, unsigned short cols)
 {
 	wchar_t *wcstr;
 	const wchar_t *p;
 	int len, cidx;
-	const unsigned short cols = getcols(fileno(stdout));
 
 	if(!str) {
 		return;
@@ -461,7 +460,7 @@ static size_t string_length(const char *s)
 	return len;
 }
 
-void string_display(const char *title, const char *string)
+void string_display(const char *title, const char *string, unsigned short cols)
 {
 	if(title) {
 		printf("%s ", title);
@@ -471,7 +470,7 @@ void string_display(const char *title, const char *string)
 	} else {
 		/* compute the length of title + a space */
 		size_t len = string_length(title) + 1;
-		indentprint(string, len);
+		indentprint(string, (unsigned short)len, cols);
 	}
 	printf("\n");
 }
@@ -603,11 +602,11 @@ static size_t table_calc_widths(const alpm_list_t *header,
  *               of headers
  * @param rows the rows to display as a list of lists of strings. the outer
  *             list represents the rows, the inner list the cells (= columns)
- *
+ * @param cols the number of columns available in the terminal
  * @return -1 if not enough terminal cols available, else 0
  */
 int table_display(const char *title, const alpm_list_t *header,
-		const alpm_list_t *rows)
+		const alpm_list_t *rows, unsigned short cols)
 {
 	const unsigned short padding = 2;
 	const alpm_list_t *i;
@@ -622,7 +621,7 @@ int table_display(const char *title, const alpm_list_t *header,
 	totalwidth = table_calc_widths(header, rows, padding, totalcols,
 			&widths, &has_data);
 	/* return -1 if terminal is not wide enough */
-	if(totalwidth > getcols(fileno(stdout))) {
+	if(totalwidth > cols) {
 		pm_printf(ALPM_LOG_WARNING,
 				_("insufficient columns available for table display\n"));
 		return -1;
@@ -647,7 +646,8 @@ int table_display(const char *title, const alpm_list_t *header,
 	return 0;
 }
 
-void list_display(const char *title, const alpm_list_t *list)
+void list_display(const char *title, const alpm_list_t *list,
+		unsigned short maxcols)
 {
 	const alpm_list_t *i;
 	size_t len = 0;
@@ -660,7 +660,6 @@ void list_display(const char *title, const alpm_list_t *list)
 	if(!list) {
 		printf("%s\n", _("None"));
 	} else {
-		const unsigned short maxcols = getcols(fileno(stdout));
 		size_t cols = len;
 		const char *str = list->data;
 		fputs(str, stdout);
@@ -688,12 +687,13 @@ void list_display(const char *title, const alpm_list_t *list)
 	}
 }
 
-void list_display_linebreak(const char *title, const alpm_list_t *list)
+void list_display_linebreak(const char *title, const alpm_list_t *list,
+		unsigned short maxcols)
 {
-	size_t len = 0;
+	unsigned short len = 0;
 
 	if(title) {
-		len = string_length(title) + 1;
+		len = (unsigned short)string_length(title) + 1;
 		printf("%s ", title);
 	}
 
@@ -702,7 +702,7 @@ void list_display_linebreak(const char *title, const alpm_list_t *list)
 	} else {
 		const alpm_list_t *i;
 		/* Print the first element */
-		indentprint((const char *)list->data, len);
+		indentprint((const char *)list->data, len, maxcols);
 		printf("\n");
 		/* Print the rest */
 		for(i = alpm_list_next(list); i; i = alpm_list_next(i)) {
@@ -710,18 +710,19 @@ void list_display_linebreak(const char *title, const alpm_list_t *list)
 			for(j = 1; j <= len; j++) {
 				printf(" ");
 			}
-			indentprint((const char *)i->data, len);
+			indentprint((const char *)i->data, len, maxcols);
 			printf("\n");
 		}
 	}
 }
 
-void signature_display(const char *title, alpm_siglist_t *siglist)
+void signature_display(const char *title, alpm_siglist_t *siglist,
+		unsigned short maxcols)
 {
-	size_t len = 0;
+	unsigned short len = 0;
 
 	if(title) {
-		len = string_length(title) + 1;
+		len = (unsigned short)string_length(title) + 1;
 		printf("%s ", title);
 	}
 	if(siglist->count == 0) {
@@ -785,7 +786,7 @@ void signature_display(const char *title, alpm_siglist_t *siglist)
 				pm_printf(ALPM_LOG_ERROR,  _("failed to allocate string\n"));
 				continue;
 			}
-			indentprint(sigline, len);
+			indentprint(sigline, len, maxcols);
 			printf("\n");
 			free(sigline);
 		}
@@ -869,6 +870,7 @@ static void _display_targets(alpm_list_t *targets, int verbose)
 	const char *label;
 	double size;
 	off_t isize = 0, rsize = 0, dlsize = 0;
+	unsigned short cols;
 	alpm_list_t *i, *rows = NULL, *names = NULL;
 
 	if(!targets) {
@@ -909,17 +911,18 @@ static void _display_targets(alpm_list_t *targets, int verbose)
 
 	/* print to screen */
 	pm_asprintf(&str, _("Targets (%d):"), alpm_list_count(targets));
-
 	printf("\n");
+
+	cols = getcols(fileno(stdout));
 	if(verbose) {
 		alpm_list_t *header = create_verbose_header();
-		if(table_display(str, header, rows) != 0) {
+		if(table_display(str, header, rows, cols) != 0) {
 			/* fallback to list display if table wouldn't fit */
-			list_display(str, names);
+			list_display(str, names, cols);
 		}
 		alpm_list_free(header);
 	} else {
-		list_display(str, names);
+		list_display(str, names, cols);
 	}
 	printf("\n");
 
@@ -1205,7 +1208,8 @@ void display_new_optdepends(alpm_pkg_t *oldpkg, alpm_pkg_t *newpkg)
 
 	if(optstrings) {
 		printf(_("New optional dependencies for %s\n"), alpm_pkg_get_name(newpkg));
-		list_display_linebreak("   ", optstrings);
+		unsigned short cols = getcols(fileno(stdout));
+		list_display_linebreak("   ", optstrings, cols);
 	}
 
 	alpm_list_free(optdeps);
@@ -1226,19 +1230,21 @@ void display_optdepends(alpm_pkg_t *pkg)
 
 	if(optstrings) {
 		printf(_("Optional dependencies for %s\n"), alpm_pkg_get_name(pkg));
-		list_display_linebreak("   ", optstrings);
+		unsigned short cols = getcols(fileno(stdout));
+		list_display_linebreak("   ", optstrings, cols);
 	}
 
 	FREELIST(optstrings);
 }
 
-static void display_repo_list(const char *dbname, alpm_list_t *list)
+static void display_repo_list(const char *dbname, alpm_list_t *list,
+		unsigned short cols)
 {
 	const char *prefix= "  ";
 
 	printf(":: ");
 	printf(_("Repository %s\n"), dbname);
-	list_display(prefix, list);
+	list_display(prefix, list, cols);
 }
 
 void select_display(const alpm_list_t *pkglist)
@@ -1248,6 +1254,7 @@ void select_display(const alpm_list_t *pkglist)
 	alpm_list_t *list = NULL;
 	char *string = NULL;
 	const char *dbname = NULL;
+	unsigned short cols = getcols(fileno(stdout));
 
 	for(i = pkglist; i; i = i->next) {
 		alpm_pkg_t *pkg = i->data;
@@ -1256,7 +1263,7 @@ void select_display(const alpm_list_t *pkglist)
 		if(!dbname)
 			dbname = alpm_db_get_name(db);
 		if(strcmp(alpm_db_get_name(db), dbname) != 0) {
-			display_repo_list(dbname, list);
+			display_repo_list(dbname, list, cols);
 			FREELIST(list);
 			dbname = alpm_db_get_name(db);
 		}
@@ -1265,7 +1272,7 @@ void select_display(const alpm_list_t *pkglist)
 		list = alpm_list_add(list, string);
 		nth++;
 	}
-	display_repo_list(dbname, list);
+	display_repo_list(dbname, list, cols);
 	FREELIST(list);
 }