[PATCH] Diff color version strings

[David Gustavsson]

In package table, with VerbosePkgLists and Color, color the part of
package version strings that changes.

Signed-off-by: David Gustavsson <david.e.gustavsson at gmail.com>
---
 src/pacman/conf.c |  4 ++++
 src/pacman/conf.h |  2 ++
 src/pacman/util.c | 35 +++++++++++++++++++++++++++++++----
 src/pacman/util.h |  1 +
 4 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/src/pacman/conf.c b/src/pacman/conf.c
index f9edf75b..d5c598b9 100644
--- a/src/pacman/conf.c
+++ b/src/pacman/conf.c
@@ -80,6 +80,8 @@ void enable_colors(int colors)
 		colstr->err     = BOLDRED;
 		colstr->faint   = GREY46;
 		colstr->nocolor = NOCOLOR;
+		colstr->diffrem = RED;
+		colstr->diffadd = GREEN;
 	} else {
 		colstr->colon   = ":: ";
 		colstr->title   = "";
@@ -91,6 +93,8 @@ void enable_colors(int colors)
 		colstr->err     = "";
 		colstr->faint   = "";
 		colstr->nocolor = "";
+		colstr->diffrem = "";
+		colstr->diffadd = "";
 	}
 }
 
diff --git a/src/pacman/conf.h b/src/pacman/conf.h
index f7916ca9..782b5758 100644
--- a/src/pacman/conf.h
+++ b/src/pacman/conf.h
@@ -33,6 +33,8 @@ typedef struct __colstr_t {
 	const char *err;
 	const char *faint;
 	const char *nocolor;
+	const char *diffrem;
+	const char *diffadd;
 } colstr_t;
 
 typedef struct __config_repo_t {
diff --git a/src/pacman/util.c b/src/pacman/util.c
index c0d62826..e998fa98 100644
--- a/src/pacman/util.c
+++ b/src/pacman/util.c
@@ -840,8 +840,10 @@ static alpm_list_t *create_verbose_row(pm_target_t *target)
 {
 	char *str;
 	off_t size = 0;
+  size_t i = 0;
 	double human_size;
 	const char *label;
+  const char *version;
 	alpm_list_t *ret = NULL;
 
 	/* a row consists of the package name, */
@@ -858,12 +860,28 @@ static alpm_list_t *create_verbose_row(pm_target_t *target)
 	add_table_cell(&ret, str, CELL_NORMAL | CELL_FREE);
 
 	/* old and new versions */
-	pm_asprintf(&str, "%s",
-			target->remove != NULL ? alpm_pkg_get_version(target->remove) : "");
+  version = alpm_pkg_get_version(target->remove);
+  char old_version[strlen(version) + strlen(config->colstr.diffrem) + strlen(config->colstr.nocolor) + 1];
+  memcpy(old_version, (char *)version, strlen(version) + 1);
+  version = alpm_pkg_get_version(target->install);
+  char new_version[strlen(version) + strlen(config->colstr.diffadd) + strlen(config->colstr.nocolor) + 1];
+  memcpy(new_version, (char *)version, strlen(version) + 1);
+
+  i = 0;
+  while (old_version[i] != '\0' && new_version[i] != '\0' && old_version[i] == new_version[i]) {
+    i++;
+  }
+  insertstring(old_version, config->colstr.diffrem, i);
+  insertstring(new_version, config->colstr.diffadd, i);
+  snprintf(old_version + i + strlen(old_version + i),
+      strlen(config->colstr.nocolor) + 1, "%s", config->colstr.nocolor);
+  snprintf(new_version + i + strlen(new_version + i),
+      strlen(config->colstr.nocolor) + 1, "%s", config->colstr.nocolor);
+
+  pm_asprintf(&str, "%s", old_version);
 	add_table_cell(&ret, str, CELL_NORMAL | CELL_FREE);
 
-	pm_asprintf(&str, "%s",
-			target->install != NULL ? alpm_pkg_get_version(target->install) : "");
+  pm_asprintf(&str, "%s", new_version);
 	add_table_cell(&ret, str, CELL_NORMAL | CELL_FREE);
 
 	/* and size */
@@ -1849,3 +1867,12 @@ void console_erase_line(void)
 {
 	printf("\x1B[K");
 }
+
+/* inserts string insert into string at index i, modifying string */
+void insertstring(char *string, const char *insert, size_t i)
+{
+  char temp[strlen(string) - i + 1];
+  memcpy(temp, string + i, strlen(string + i) + 1);
+  memcpy(string + i, insert, strlen(insert) + 1);
+  memcpy(string + i + strlen(insert), temp, strlen(temp) + 1);
+}
diff --git a/src/pacman/util.h b/src/pacman/util.h
index 52e79915..003961eb 100644
--- a/src/pacman/util.h
+++ b/src/pacman/util.h
@@ -88,6 +88,7 @@ void console_cursor_move_down(unsigned int lines);
 void console_cursor_move_end(void);
 /* Erases line from the current cursor position till the end of the line */
 void console_erase_line(void);
+void insertstring(char *string, const char *insert, size_t i);
 
 int pm_printf(alpm_loglevel_t level, const char *format, ...) __attribute__((format(printf,2,3)));
 int pm_asprintf(char **string, const char *format, ...) __attribute__((format(printf,2,3)));
-- 
2.34.1