vi: expand '%' and '#' in colon commands

Track the current and alternate filenames.  The placeholders '%'
and '#' can be used in arguments to colon commands to represent
the current and alternate filenames respectively.  Backslash can
be used to allow literal '%' and '#' characters to be entered.

This feature is controlled by the configuration option
FEATURE_VI_COLON_EXPAND.

function                                             old     new   delta
expand_args                                            -     198    +198
colon                                               3751    3927    +176
update_filename                                        -      70     +70
init_filename                                          -      48     +48
.rodata                                           105218  105239     +21
get_one_char                                         115     124      +9
edit_file                                            835     838      +3
do_cmd                                              4724    4727      +3
init_text_buffer                                     190     172     -18
------------------------------------------------------------------------------
(add/remove: 3/0 grow/shrink: 5/1 up/down: 528/-18)           Total: 510 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 112 insertions, 14 deletions

diff --git a/editors/vi.c b/editors/vi.c
index 715961019..6a879fa8a 100644
--- a/editors/vi.c
+++ b/editors/vi.c
@@ -53,6 +53,14 @@
 //config:       Enable a limited set of colon commands. This does not
 //config:       provide an "ex" mode.
 //config:
+//config:config FEATURE_VI_COLON_EXPAND
+//config:       bool "Expand \"%\" and \"#\" in colon commands"
+//config:       default y
+//config:       depends on FEATURE_VI_COLON
+//config:       help
+//config:       Expand the special characters \"%\" (current filename)
+//config:       and \"#\" (alternate filename) in colon commands.
+//config:
 //config:config FEATURE_VI_YANKMARK
 //config:       bool "Enable yank/put commands and mark cmds"
 //config:       default y
@@ -347,6 +355,9 @@ struct globals {
                                  // [don't make smallint!]
         int last_status_cksum;   // hash of current status line
         char *current_filename;
+#if ENABLE_FEATURE_VI_COLON_EXPAND
+        char *alt_filename;
+#endif
         char *screenbegin;       // index into text[], of top line on the screen
         char *screen;            // pointer to the virtual screen buffer
         int screensize;          //            and its size
@@ -471,6 +482,7 @@ struct globals {
 #define have_status_msg         (G.have_status_msg    )
 #define last_status_cksum       (G.last_status_cksum  )
 #define current_filename        (G.current_filename   )
+#define alt_filename            (G.alt_filename       )
 #define screen                  (G.screen             )
 #define screensize              (G.screensize         )
 #define screenbegin             (G.screenbegin        )
@@ -2198,6 +2210,41 @@ static char *char_insert(char *p, char c, int undo) // insert the char c at 'p'
         return p;
 }
 
+#if ENABLE_FEATURE_VI_COLON_EXPAND
+static void init_filename(char *fn)
+{
+        char *copy = xstrdup(fn);
+
+        if (current_filename == NULL) {
+                current_filename = copy;
+        } else {
+                free(alt_filename);
+                alt_filename = copy;
+        }
+}
+#else
+# define init_filename(f) ((void)(0))
+#endif
+
+static void update_filename(char *fn)
+{
+#if ENABLE_FEATURE_VI_COLON_EXPAND
+        if (fn == NULL)
+                return;
+
+        if (current_filename == NULL || strcmp(fn, current_filename) != 0) {
+                free(alt_filename);
+                alt_filename = current_filename;
+                current_filename = xstrdup(fn);
+        }
+#else
+        if (fn != current_filename) {
+                free(current_filename);
+                current_filename = xstrdup(fn);
+        }
+#endif
+}
+
 // read text from file or create an empty buf
 // will also update current_filename
 static int init_text_buffer(char *fn)
@@ -2209,10 +2256,7 @@ static int init_text_buffer(char *fn)
         text_size = 10240;
         screenbegin = dot = end = text = xzalloc(text_size);
 
-        if (fn != current_filename) {
-                free(current_filename);
-                current_filename = xstrdup(fn);
-        }
+        update_filename(fn);
         rc = file_insert(fn, text, 1);
         if (rc < 0) {
                 // file doesnt exist. Start empty buf with dummy line
@@ -2556,6 +2600,43 @@ static void setops(char *args, int flg_no)
 }
 # endif
 
+# if ENABLE_FEATURE_VI_COLON_EXPAND
+static char *expand_args(char *args)
+{
+        char *s, *t;
+        const char *replace;
+
+        args = xstrdup(args);
+        for (s = args; *s; s++) {
+                if (*s == '%') {
+                        replace = current_filename;
+                } else if (*s == '#') {
+                        replace = alt_filename;
+                } else {
+                        if (*s == '\\' && s[1] != '\0') {
+                                for (t = s++; *t; t++)
+                                        *t = t[1];
+                        }
+                        continue;
+                }
+
+                if (replace == NULL) {
+                        free(args);
+                        status_line_bold("No previous filename");
+                        return NULL;
+                }
+
+                *s = '\0';
+                t = xasprintf("%s%s%s", args, replace, s+1);
+                s = t + (s - args) + strlen(replace);
+                free(args);
+                args = t;
+        }
+        return args;
+}
+# else
+#  define expand_args(a) (a)
+# endif
 #endif /* FEATURE_VI_COLON */
 
 // buf must be no longer than MAX_INPUT_LEN!
@@ -2620,7 +2701,7 @@ static void colon(char *buf)
 #else
 
         char c, *buf1, *q, *r;
-        char *fn, cmd[MAX_INPUT_LEN], *cmdend, *args;
+        char *fn, cmd[MAX_INPUT_LEN], *cmdend, *args, *exp = NULL;
         int i, l, li, b, e;
         int useforce;
 
@@ -2708,9 +2789,12 @@ static void colon(char *buf)
         else if (cmd[0] == '!') {       // run a cmd
                 int retcode;
                 // :!ls   run the <cmd>
+                exp = expand_args(buf + 1);
+                if (exp == NULL)
+                        goto ret;
                 go_bottom_and_clear_to_eol();
                 cookmode();
-                retcode = system(buf + 1);      // run the cmd
+                retcode = system(exp);  // run the cmd
                 if (retcode)
                         printf("\nshell returned %i\n\n", retcode);
                 rawmode();
@@ -2739,7 +2823,9 @@ static void colon(char *buf)
                 }
                 if (args[0]) {
                         // the user supplied a file name
-                        fn = args;
+                        fn = exp = expand_args(args);
+                        if (exp == NULL)
+                                goto ret;
                 } else if (current_filename == NULL) {
                         // no user file name, no current name- punt
                         status_line_bold("No current filename");
@@ -2763,7 +2849,7 @@ static void colon(char *buf)
                 status_line("'%s'%s"
                         IF_FEATURE_VI_READONLY("%s")
                         " %uL, %uC",
-                        current_filename,
+                        fn,
                         (size < 0 ? " [New file]" : ""),
                         IF_FEATURE_VI_READONLY(
                                 ((readonly_mode) ? " [Readonly]" : ""),
@@ -2777,8 +2863,10 @@ static void colon(char *buf)
                 }
                 if (args[0]) {
                         // user wants a new filename
-                        free(current_filename);
-                        current_filename = xstrdup(args);
+                        exp = expand_args(args);
+                        if (exp == NULL)
+                                goto ret;
+                        update_filename(exp);
                 } else {
                         // user wants file status info
                         last_status_cksum = 0;  // force status update
@@ -2862,7 +2950,10 @@ static void colon(char *buf)
 
                 if (args[0]) {
                         // the user supplied a file name
-                        fn = args;
+                        fn = exp = expand_args(args);
+                        if (exp == NULL)
+                                goto ret;
+                        init_filename(fn);
                 } else if (current_filename == NULL) {
                         // no user file name, no current name- punt
                         status_line_bold("No current filename");
@@ -3042,12 +3133,16 @@ static void colon(char *buf)
                 if (args[0]) {
                         struct stat statbuf;
 
-                        if (!useforce && (fn == NULL || strcmp(fn, args) != 0) &&
-                                        stat(args, &statbuf) == 0) {
+                        exp = expand_args(args);
+                        if (exp == NULL)
+                                goto ret;
+                        if (!useforce && (fn == NULL || strcmp(fn, exp) != 0) &&
+                                        stat(exp, &statbuf) == 0) {
                                 status_line_bold("File exists (:w! overrides)");
                                 goto ret;
                         }
-                        fn = args;
+                        fn = exp;
+                        init_filename(fn);
                 }
 # if ENABLE_FEATURE_VI_READONLY
                 else if (readonly_mode && !useforce && fn) {
@@ -3109,6 +3204,9 @@ static void colon(char *buf)
                 not_implemented(cmd);
         }
  ret:
+# if ENABLE_FEATURE_VI_COLON_EXPAND
+        free(exp);
+# endif
         dot = bound_dot(dot);   // make sure "dot" is valid
         return;
 # if ENABLE_FEATURE_VI_SEARCH