Add color output to zfs diff.

This adds support to color zfs diff (in the style of git diff)
conditional on the ZFS_COLOR environment variable.

Signed-off-by: Ethan Coe-Renner <[email protected]>

4 files changed, 53 insertions, 2 deletions

diff --git a/include/libzutil.h b/include/libzutil.h
index 617dd0cd1..e285183e0 100644
--- a/include/libzutil.h
+++ b/include/libzutil.h
@@ -170,7 +170,9 @@ struct zfs_cmd;
  * List of colors to use
  */
 #define	ANSI_RED	"\033[0;31m"
+#define	ANSI_GREEN	"\033[0;32m"
 #define	ANSI_YELLOW	"\033[0;33m"
+#define	ANSI_BLUE	"\033[0;34m"
 #define	ANSI_RESET	"\033[0m"
 #define	ANSI_BOLD	"\033[1m"
 
diff --git a/lib/libzfs/libzfs_diff.c b/lib/libzfs/libzfs_diff.c
index 84e140ede..1330e7c30 100644
--- a/lib/libzfs/libzfs_diff.c
+++ b/lib/libzfs/libzfs_diff.c
@@ -44,6 +44,7 @@
 #include <pthread.h>
 #include <sys/zfs_ioctl.h>
 #include <libzfs.h>
+#include <libzutil.h>
 #include "libzfs_impl.h"
 
 #define	ZDIFF_SNAPDIR		"/.zfs/snapshot/"
@@ -54,6 +55,10 @@
 #define	ZDIFF_REMOVED	'-'
 #define	ZDIFF_RENAMED	"R"
 
+#define	ZDIFF_ADDED_COLOR ANSI_GREEN
+#define	ZDIFF_MODIFIED_COLOR ANSI_YELLOW
+#define	ZDIFF_REMOVED_COLOR ANSI_RED
+#define	ZDIFF_RENAMED_COLOR ANSI_BLUE
 
 /*
  * Given a {dsname, object id}, get the object path
@@ -128,6 +133,25 @@ stream_bytes(FILE *fp, const char *string)
 	}
 }
 
+/*
+ * Takes the type of change (like `print_file`), outputs the appropriate color
+ */
+static const char *
+type_to_color(char type)
+{
+	if (type == '+')
+		return (ZDIFF_ADDED_COLOR);
+	else if (type == '-')
+		return (ZDIFF_REMOVED_COLOR);
+	else if (type == 'M')
+		return (ZDIFF_MODIFIED_COLOR);
+	else if (type == 'R')
+		return (ZDIFF_RENAMED_COLOR);
+	else
+		return (NULL);
+}
+
+
 static char
 get_what(mode_t what)
 {
@@ -175,6 +199,8 @@ static void
 print_rename(FILE *fp, differ_info_t *di, const char *old, const char *new,
     zfs_stat_t *isb)
 {
+	if (isatty(fileno(fp)))
+		color_start(ZDIFF_RENAMED_COLOR);
 	if (di->timestamped)
 		(void) fprintf(fp, "%10lld.%09lld\t",
 		    (longlong_t)isb->zs_ctime[0],
@@ -186,12 +212,18 @@ print_rename(FILE *fp, differ_info_t *di, const char *old, const char *new,
 	(void) fputs(di->scripted ? "\t" : " -> ", fp);
 	print_cmn(fp, di, new);
 	(void) fputc('\n', fp);
+
+	if (isatty(fileno(fp)))
+		color_end();
 }
 
 static void
 print_link_change(FILE *fp, differ_info_t *di, int delta, const char *file,
     zfs_stat_t *isb)
 {
+	if (isatty(fileno(fp)))
+		color_start(ZDIFF_MODIFIED_COLOR);
+
 	if (di->timestamped)
 		(void) fprintf(fp, "%10lld.%09lld\t",
 		    (longlong_t)isb->zs_ctime[0],
@@ -201,12 +233,17 @@ print_link_change(FILE *fp, differ_info_t *di, int delta, const char *file,
 		(void) fprintf(fp, "%c\t", get_what(isb->zs_mode));
 	print_cmn(fp, di, file);
 	(void) fprintf(fp, "\t(%+d)\n", delta);
+	if (isatty(fileno(fp)))
+		color_end();
 }
 
 static void
 print_file(FILE *fp, differ_info_t *di, char type, const char *file,
     zfs_stat_t *isb)
 {
+	if (isatty(fileno(fp)))
+		color_start(type_to_color(type));
+
 	if (di->timestamped)
 		(void) fprintf(fp, "%10lld.%09lld\t",
 		    (longlong_t)isb->zs_ctime[0],
@@ -216,6 +253,9 @@ print_file(FILE *fp, differ_info_t *di, char type, const char *file,
 		(void) fprintf(fp, "%c\t", get_what(isb->zs_mode));
 	print_cmn(fp, di, file);
 	(void) fputc('\n', fp);
+
+	if (isatty(fileno(fp)))
+		color_end();
 }
 
 static int
diff --git a/lib/libzfs/libzfs_util.c b/lib/libzfs/libzfs_util.c
index b4679dbb3..c31f18009 100644
--- a/lib/libzfs/libzfs_util.c
+++ b/lib/libzfs/libzfs_util.c
@@ -2010,15 +2010,20 @@ use_color(void)
 void
 color_start(const char *color)
 {
-	if (use_color())
+	if (use_color()) {
 		fputs(color, stdout);
+		fflush(stdout);
+	}
 }
 
 void
 color_end(void)
 {
-	if (use_color())
+	if (use_color()) {
 		fputs(ANSI_RESET, stdout);
+		fflush(stdout);
+	}
+
 }
 
 /* printf() with a color.  If color is NULL, then do a normal printf. */
diff --git a/man/man8/zfs.8 b/man/man8/zfs.8
index 52c079257..d12377f9b 100644
--- a/man/man8/zfs.8
+++ b/man/man8/zfs.8
@@ -737,6 +737,10 @@ command will be undone if the share is ever unshared (like via a reboot).
 .
 .Sh ENVIRONMENT VARIABLES
 .Bl -tag -width "ZFS_MODULE_TIMEOUT"
+.It Sy ZFS_COLOR
+Use ANSI color in
+.Nm zfs Cm diff
+output.
 .It Sy ZFS_MOUNT_HELPER
 Cause
 .Nm zfs Cm mount