[1/2] Btrfs-progs: Improve the command help system of btrfs

Commit Message

Chen Yang Oct. 25, 2012, 8:49 a.m. UTC

Btrfs's command help system allow you to show only one line short usage.
But in some case we need to use two or more lines to show
the short usage of a complicated command.

This patch add a filed 'lines' in cmd_struct, which is the number of the
extra short usage lines you want to append.

For example you have N lines short usage; you should set the field 'lines'
to N-1.

Signed-off-by: Cheng Yang <[e-mail]>
---
 commands.h |    4 ++++
 help.c     |   31 ++++++++++++++++++++++---------
 2 files changed, 26 insertions(+), 9 deletions(-)

Patch

diff --git a/commands.h b/commands.h
index bb6d2dd..f535dc2 100644
--- a/commands.h
+++ b/commands.h
@@ -48,6 +48,9 @@  struct cmd_struct {
 
 	/* if true don't list this token in help listings */
 	int hidden;
+
+	/* number of the extra short usage lines  */
+	int lines;
 };
 
 struct cmd_group {
@@ -70,6 +73,7 @@  int handle_command_group(const struct cmd_group *grp, int argc,
 /* help.c */
 extern const char * const generic_cmd_help_usage[];
 
+void usage_lines(const char * const *usagestr, int lines);
 void usage(const char * const *usagestr);
 void usage_command(const struct cmd_struct *cmd, int full, int err);
 void usage_command_group(const struct cmd_group *grp, int all, int err);
diff --git a/help.c b/help.c
index 6d04293..5679933 100644
--- a/help.c
+++ b/help.c
@@ -28,15 +28,21 @@  extern char argv0_buf[ARGV0_BUF_SIZE];
 #define USAGE_LISTING		8U
 
 static int do_usage_one_command(const char * const *usagestr,
-				unsigned int flags, FILE *outf)
+				unsigned int flags, FILE *outf, int lines)
 {
-	int pad = 4;
+	int pad = 4, i = 0;
 
 	if (!usagestr || !*usagestr)
 		return -1;
 
 	fprintf(outf, "%s%s\n", (flags & USAGE_LISTING) ? "    " : "usage: ",
 		*usagestr++);
+	for (i = 0; i < lines; i++) {
+		fprintf(outf, "%s%s\n",
+			(flags & USAGE_LISTING) ? "    " : "       ",
+			usagestr[i]);
+	}
+	usagestr += lines;
 
 	/* a short one-line description (mandatory) */
 	if ((flags & USAGE_SHORT) == 0)
@@ -79,7 +85,7 @@  static int do_usage_one_command(const char * const *usagestr,
 
 static int usage_command_internal(const char * const *usagestr,
 				  const char *token, int full, int lst,
-				  FILE *outf)
+				  FILE *outf, int lines)
 {
 	unsigned int flags = USAGE_SHORT;
 	int ret;
@@ -89,7 +95,7 @@  static int usage_command_internal(const char * const *usagestr,
 	if (lst)
 		flags |= USAGE_LISTING;
 
-	ret = do_usage_one_command(usagestr, flags, outf);
+	ret = do_usage_one_command(usagestr, flags, outf, lines);
 	switch (ret) {
 	case -1:
 		fprintf(outf, "No usage for '%s'\n", token);
@@ -103,24 +109,31 @@  static int usage_command_internal(const char * const *usagestr,
 }
 
 static void usage_command_usagestr(const char * const *usagestr,
-				   const char *token, int full, int err)
+			   const char *token, int full, int err, int lines)
 {
 	FILE *outf = err ? stderr : stdout;
 	int ret;
 
-	ret = usage_command_internal(usagestr, token, full, 0, outf);
+	ret = usage_command_internal(usagestr, token, full, 0, outf, lines);
 	if (!ret)
 		fputc('\n', outf);
 }
 
 void usage_command(const struct cmd_struct *cmd, int full, int err)
 {
-	usage_command_usagestr(cmd->usagestr, cmd->token, full, err);
+	usage_command_usagestr(
+		cmd->usagestr, cmd->token, full, err, cmd->lines);
 }
 
 void usage(const char * const *usagestr)
 {
-	usage_command_usagestr(usagestr, NULL, 1, 1);
+	usage_lines(usagestr, 0);
+	exit(129);
+}
+
+void usage_lines(const char * const *usagestr, int lines)
+{
+	usage_command_usagestr(usagestr, NULL, 1, 1, lines);
 	exit(129);
 }
 
@@ -144,7 +157,7 @@  static void usage_command_group_internal(const struct cmd_group *grp, int full,
 			}
 
 			usage_command_internal(cmd->usagestr, cmd->token, full,
-					       1, outf);
+					       1, outf, cmd->lines);
 			continue;
 		}