Support for e-command abbreviation

doc/vitunes.1

@@ -235,6 +235,14 @@ section for a complete listing.
 More detailed usage information and examples for each e-command can be
 obtained by issuing:
 .Dl $ vitunes -e help command-name
+.Pp
+Note that abbreviations are also supported.
+That is, entering any non-ambiguous abbreviation of an e-command will also
+execute the e-command.
+.Bd -literal -offset indent
+$ vitunes -e a ~/music
+vitunes: Ambiguous e-command 'a'.  Matches: add addurl
+.Ed
 .Sh RUN-TIME COMMANDS
 Below is a listing of all run-time commands supported by
 .Nm .
@@ -243,9 +251,7 @@ All commands are entered by typing ':' followed by the command name and any
 parameters (just like in
 .Xr vi 1 ).
 .Pp
-Note that abbreviations are also supported.
-That is, entering any non-ambiguous abbreviation of a command name will also
-execute the command.
+As with e-commands, abbreviations are also supported.
 .Bl -tag -width Ds
 .It Pf : Ic bind Ar action Ar keycode
 This will bind the action specified by

ecmd.c

@@ -17,6 +17,20 @@
 
 #include "ecmd.h"
 
+/* set of e-commands */
+static const struct ecmd *ecmdtab[] = {
+   &ecmd_add,
+   &ecmd_addurl,
+   &ecmd_check,
+   &ecmd_flush,
+   &ecmd_help,
+   &ecmd_init,
+   &ecmd_rmfile,
+   &ecmd_tag,
+   &ecmd_update,
+};
+static const int ecmdtab_size = sizeof ecmdtab / sizeof ecmdtab[0];
+
 static int
 ecmd_parse(const struct ecmd *ecmd, int argc, char ***argv)
 {
@@ -45,49 +59,79 @@ ecmd_parse(const struct ecmd *ecmd, int argc, char ***argv)
    if (ecmd->args_upper >= 0 && argc > ecmd->args_upper)
       return -1;
 
-   /* return updated (no name) number of arguments */
+   /* return updated number of arguments */
    return argc;
 }
 
+static void
+ecmd_print_ambiguous(const char *ecmd)
+{
+   int i;
+
+   fprintf(stderr, "%s: Ambiguous e-command '%s'.  Matches: ", progname, ecmd);
+   for (i = 0; i < ecmdtab_size; i++) {
+      if (strncmp(ecmd, ecmdtab[i]->name, strlen(ecmd)) != 0)
+          continue;
+      fprintf(stderr, "%s ", ecmdtab[i]->name);
+   }
+   fputs("\n", stderr);
+}
+
+const char *
+ecmd_get_names(void)
+{
+   static int         i = 0;
+   const struct ecmd *ecmdp;
+
+   if (i == ecmdtab_size)
+      return (NULL);
+
+   ecmdp = ecmdtab[i++];
+   return (ecmdp->name);
+}
+
 int
 ecmd_exec(const char *ecmd, int argc, char **argv)
 {
-   /* set of e-commands */
-   static const struct ecmd *ecmdtab[] = {
-      &ecmd_add,
-      &ecmd_addurl,
-      &ecmd_check,
-      &ecmd_flush,
-      &ecmd_help,
-      &ecmd_init,
-      &ecmd_rmfile,
-      &ecmd_tag,
-      &ecmd_update,
-   };
-   static const int ecmdtab_size = sizeof ecmdtab / sizeof ecmdtab[0];
-   int              i;
+   bool               ambiguous = false;
+   int                i;
+   const struct ecmd *ecmdp = NULL;
 
-   /* search for e-command (first by name and then by alias) */
+   /* search for e-command (first by name and then by abbreviation) */
    for (i = 0; i < ecmdtab_size; i++) {
-      if (strcmp(ecmd, ecmdtab[i]->name) == 0)
+      /* exact match */
+      if (strcmp(ecmd, ecmdtab[i]->name) == 0) {
+         ecmdp = ecmdtab[i];
          break;
-      if (ecmdtab[i]->alias != NULL && strcmp(ecmd, ecmdtab[i]->alias) == 0)
+      }
+      /* abbreviation match */
+      if (strncmp(ecmd, ecmdtab[i]->name, strlen(ecmd)) != 0)
+         continue;
+      if (ecmdp != NULL) {
+         ambiguous = true;
          break;
+      }
+      ecmdp = ecmdtab[i];
    }
    /* not found; bail out */
-   if (i == ecmdtab_size) {
+   if (ecmdp == NULL) {
       warnx("Unknown e-command '%s'.  See 'vitunes -e help' for list.", ecmd);
       return -1;
    }
+   /* ambiguous e-command */
+   if (ambiguous) {
+      ecmd_print_ambiguous(ecmd);
+      return -1;
+   }
 
    /* parse e-command arguments */
-   if ((argc = ecmd_parse(ecmdtab[i], argc, &argv)) == -1) {
-      fprintf(stderr, "usage: %s -e %s %s\n", progname, ecmdtab[i]->name,
-          ecmdtab[i]->usage != NULL ? ecmdtab[i]->usage : "");
+   if ((argc = ecmd_parse(ecmdp, argc, &argv)) == -1) {
+      fprintf(stderr, "usage: %s -e %s %s\n", progname, ecmdp->name,
+          ecmdp->usage != NULL ? ecmdp->usage : "");
       return 1;
    }
 
    /* finally execute it */
-   ecmdtab[i]->exec(argc, argv);
+   ecmdp->exec(argc, argv);
    return 0;
 }

ecmd.h

@@ -19,6 +19,7 @@
 #define ECMD_H
 
 #include <err.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
@@ -27,7 +28,6 @@
 
 struct ecmd {
    const char  *name;
-   const char  *alias;      /* may be NULL */
    const char  *usage;      /* may be NULL */
    int          args_lower; /* minimum number of arguments */
    int          args_upper; /* negative number means no limit */
@@ -46,6 +46,7 @@ extern const struct ecmd ecmd_rmfile;
 extern const struct ecmd ecmd_tag;
 extern const struct ecmd ecmd_update;
 
-int ecmd_exec(const char *ecmd, int argc, char **argv);
+const char *ecmd_get_names(void);
+int         ecmd_exec(const char *ecmd, int argc, char **argv);
 
 #endif

ecmd_add.c

@@ -34,7 +34,7 @@ ecmd_add_exec(UNUSED int argc, char **argv)
 }
 
 const struct ecmd ecmd_add = {
-   "add", NULL,
+   "add",
    "path [...]",
    1, -1,
    NULL,

ecmd_addurl.c

@@ -94,7 +94,7 @@ ecmd_addurl_exec(UNUSED int argc, char **argv)
 }
 
 const struct ecmd ecmd_addurl = {
-   "addurl", NULL,
+   "addurl",
    "URL|path",
    1, 1,
    NULL,

ecmd_check.c

@@ -151,7 +151,7 @@ ecmd_check_exec(int argc, char **argv)
 }
 
 const struct ecmd ecmd_check = {
-   "check", NULL,
+   "check",
    "-d | -r | -s path [...]",
    1, -1,
    ecmd_check_parse,

ecmd_flush.c

@@ -55,7 +55,7 @@ ecmd_flush_exec(UNUSED int argc, UNUSED char **argv)
 }
 
 const struct ecmd ecmd_flush = {
-   "flush", NULL,
+   "flush",
    "[-t format]",
    0, 0,
    ecmd_flush_parse,

ecmd_help.c

@@ -26,30 +26,19 @@
 static void
 ecmd_help_exec(UNUSED int argc, char **argv)
 {
-   char *man_args[3];
+   char       *man_args[3];
+   const char *name;
 
    /* no help requested for a specific command, give a list of all e-cmds */
    if (argc == 0) {
-      printf("\
-The following is a list of e-commands supported by vitunes.\n\
-Each command is executed by doing:\n\
-   $ vitunes -e COMMAND [args ...]\n\
-The complete manual for each can be obtained by doing:\n\
-   $ vitunes -e help COMMAND\n\
-The list of available commands are:\n\n\
-   Command     Description\n\
-   -------     ------------------------------------------------------------\n\
-   add         Add files to the database.\n\
-   addurl      Add URL (or non-file playable item) to the database.\n\
-   check       Check files for meta-information.\n\
-   flush       Output the contents of the database to stdout.\n\
-   help        This command.\n\
-   init        Initialize the media database.\n\
-   rm          Remove a file or a URL from the database.\n\
-   rmfile      Alias for \"rm\".\n\
-   tag         Set the meta-information tags in media files.\n\
-   update      Update all files in the database.\n\
-");
+      printf("Available e-commands: ");
+      while ((name = ecmd_get_names()) != NULL)
+         printf("%s ", name);
+      puts("\n");
+      printf("Each is executed by doing:\n"
+         "$ vitunes -e e-command [...]\n"
+         "The complete manual for each can be obtained by doing:\n"
+         "$ vitunes -e help e-command\n");
       return;
    }
 
@@ -69,7 +58,7 @@ The list of available commands are:\n\n\
 }
 
 const struct ecmd ecmd_help = {
-   "help", NULL,
+   "help",
    "[command]",
    0, 1,
    NULL,

ecmd_init.c

@@ -31,7 +31,7 @@ ecmd_init_exec(UNUSED int argc, UNUSED char **argv)
 }
 
 const struct ecmd ecmd_init = {
-   "init", NULL,
+   "init",
    NULL,
    0, 0,
    NULL,

ecmd_rmfile.c

@@ -86,7 +86,7 @@ ecmd_rmfile_exec(UNUSED int argc, char **argv)
 }
 
 const struct ecmd ecmd_rmfile = {
-   "rmfile", "rm",
+   "rmfile",
    "[-f] URL|path",
    1, 1,
    ecmd_rmfile_parse,

ecmd_tag.c

@@ -144,7 +144,7 @@ ecmd_tag_exec(int argc, char **argv)
 }
 
 const struct ecmd ecmd_tag = {
-   "tag", NULL,
+   "tag",
    "[-A album] [-T track] [-a artist] [-c comment] [-g genre] [-t title]\n\
    \t[-y year] path [...]",
    1, -1,

ecmd_update.c

@@ -62,7 +62,7 @@ ecmd_update_exec(UNUSED int argc, UNUSED char **argv)
 }
 
 const struct ecmd ecmd_update = {
-   "update", NULL,
+   "update",
    "[-fs]",
    0, 0,
    ecmd_update_parse,