Add true and false commands; repartition some logic to better support forthcoming looping

4 files changed, 133 insertions, 57 deletions

diff --git a/apps/nshlib/nsh.h b/apps/nshlib/nsh.h
index a38d04c4a..a9db6e5d2 100644
--- a/apps/nshlib/nsh.h
+++ b/apps/nshlib/nsh.h
@@ -1,7 +1,7 @@
 /****************************************************************************
  * apps/nshlib/nsh.h
  *
- *   Copyright (C) 2007-2013 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2014 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -453,23 +453,28 @@
 /****************************************************************************
  * Public Types
  ****************************************************************************/
+/* State when parsing and if-then-else sequence */
 
 enum nsh_parser_e
 {
-   NSH_PARSER_NORMAL = 0,
-   NSH_PARSER_IF,
-   NSH_PARSER_THEN,
-   NSH_PARSER_ELSE
+   NSH_PARSER_NORMAL = 0,  /* Not in any special sequence */
+   NSH_PARSER_IF,          /* Just parsed 'if', expect condition */
+   NSH_PARSER_THEN,        /* Just parsed 'then', looking for 'else' or 'fi' */
+   NSH_PARSER_ELSE         /* Just parsed 'else', look for 'fi' */
 };
 
-struct nsh_state_s
+/* All state data for parsing one if-then-else sequence */
+
+struct nsh_ifthenelse_s
 {
-  uint8_t   ns_ifcond   : 1; /* Value of command in 'if' statement */
-  uint8_t   ns_disabled : 1; /* TRUE: Unconditionally disabled */
-  uint8_t   ns_unused   : 4;
-  uint8_t   ns_state    : 2; /* Parser state (see enum nsh_parser_e) */
+  uint8_t   ie_ifcond   : 1; /* Value of command in 'if' statement */
+  uint8_t   ie_disabled : 1; /* TRUE: Unconditionally disabled */
+  uint8_t   ie_unused   : 4;
+  uint8_t   ie_state    : 2; /* Parser state (see enum nsh_parser_e) */
 };
 
+/* These structure provides the overall state of the parser */
+
 struct nsh_parser_s
 {
 #ifndef CONFIG_NSH_DISABLEBG
@@ -479,19 +484,17 @@ struct nsh_parser_s
   bool    np_redirect; /* true: Output from the last command was re-directed */
 #endif
   bool    np_fail;     /* true: The last command failed */
-#ifndef CONFIG_NSH_DISABLESCRIPT
-  uint8_t np_ndx;      /* Current index into np_st[] */
-#endif
 #ifndef CONFIG_NSH_DISABLEBG
   int     np_nice;     /* "nice" value applied to last background cmd */
 #endif
 
-  /* This is a stack of parser state information.  It supports nested
-   * execution of commands that span multiple lines (like if-then-else-fi)
-   */
-
 #ifndef CONFIG_NSH_DISABLESCRIPT
-  struct nsh_state_s np_st[CONFIG_NSH_NESTDEPTH];
+  FILE   *np_stream;   /* Stream of current script */
+  uint8_t np_iendx;    /* Current index into np_iestate[] */
+
+  /* This is a stack of if-then-else state information. */
+
+  struct nsh_ifthenelse_s np_iestate[CONFIG_NSH_NESTDEPTH];
 #endif
 };
 
diff --git a/apps/nshlib/nsh_command.c b/apps/nshlib/nsh_command.c
index faf64bbe5..8321ad876 100644
--- a/apps/nshlib/nsh_command.c
+++ b/apps/nshlib/nsh_command.c
@@ -81,9 +81,15 @@ struct cmdmap_s
 static int  cmd_help(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
 #endif
 
+#ifndef CONFIG_NSH_DISABLESCRIPT
+static int  cmd_true(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
+static int  cmd_false(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
+#endif
+
 #ifndef CONFIG_NSH_DISABLE_EXIT
 static int  cmd_exit(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
 #endif
+
 static int  cmd_unrecognized(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
 
 /****************************************************************************
@@ -167,10 +173,15 @@ static const struct cmdmap_s g_cmdmap[] =
 #ifndef CONFIG_NSH_DISABLE_EXEC
   { "exec",     cmd_exec,     2, 3, "<hex-address>" },
 #endif
+
 #ifndef CONFIG_NSH_DISABLE_EXIT
   { "exit",     cmd_exit,     1, 1, NULL },
 #endif
 
+#ifndef CONFIG_NSH_DISABLESCRIPT
+  { "false",     cmd_false,    1, 1, NULL },
+#endif
+
 #ifndef CONFIG_NSH_DISABLE_FREE
   { "free",     cmd_free,     1, 1, NULL },
 #endif
@@ -356,6 +367,10 @@ static const struct cmdmap_s g_cmdmap[] =
   { "test",     cmd_test,     3, CONFIG_NSH_MAXARGUMENTS, "<expression>" },
 #endif
 
+#ifndef CONFIG_NSH_DISABLESCRIPT
+  { "true",     cmd_true,    1, 1, NULL },
+#endif
+
 #if !defined(CONFIG_DISABLE_MOUNTPOINT) && CONFIG_NFILE_DESCRIPTORS > 0 && defined(CONFIG_FS_READABLE)
 # ifndef CONFIG_NSH_DISABLE_UMOUNT
   { "umount",   cmd_umount,   2, 2, "<dir-path>" },
@@ -645,6 +660,29 @@ static int cmd_unrecognized(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
 }
 
 /****************************************************************************
+ * Name: cmd_true
+ ****************************************************************************/
+
+#ifndef CONFIG_NSH_DISABLESCRIPT
+static int cmd_true(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
+{
+  return OK;
+}
+
+#endif
+
+/****************************************************************************
+ * Name: cmd_false
+ ****************************************************************************/
+
+#ifndef CONFIG_NSH_DISABLESCRIPT
+static int cmd_false(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
+{
+  return ERROR;
+}
+#endif
+
+/****************************************************************************
  * Name: cmd_exit
  ****************************************************************************/
 
diff --git a/apps/nshlib/nsh_parse.c b/apps/nshlib/nsh_parse.c
index c7ef521a1..a83b9e999 100644
--- a/apps/nshlib/nsh_parse.c
+++ b/apps/nshlib/nsh_parse.c
@@ -392,10 +392,10 @@ static int nsh_saveresult(FAR struct nsh_vtbl_s *vtbl, bool result)
   struct nsh_parser_s *np = &vtbl->np;
 
 #ifndef CONFIG_NSH_DISABLESCRIPT
-  if (np->np_st[np->np_ndx].ns_state == NSH_PARSER_IF)
+  if (np->np_iestate[np->np_iendx].ie_state == NSH_PARSER_IF)
     {
       np->np_fail = false;
-      np->np_st[np->np_ndx].ns_ifcond = result;
+      np->np_iestate[np->np_iendx].ie_ifcond = result;
       return OK;
     }
   else
@@ -1335,10 +1335,10 @@ static FAR char *nsh_argument(FAR struct nsh_vtbl_s *vtbl, FAR char **saveptr,
 static bool nsh_cmdenabled(FAR struct nsh_vtbl_s *vtbl)
 {
   struct nsh_parser_s *np = &vtbl->np;
-  bool ret = !np->np_st[np->np_ndx].ns_disabled;
+  bool ret = !np->np_iestate[np->np_iendx].ie_disabled;
   if (ret)
     {
-      switch (np->np_st[np->np_ndx].ns_state)
+      switch (np->np_iestate[np->np_iendx].ie_state)
         {
           case NSH_PARSER_NORMAL :
           case NSH_PARSER_IF:
@@ -1346,11 +1346,11 @@ static bool nsh_cmdenabled(FAR struct nsh_vtbl_s *vtbl)
             break;
 
           case NSH_PARSER_THEN:
-            ret = !np->np_st[np->np_ndx].ns_ifcond;
+            ret = !np->np_iestate[np->np_iendx].ie_ifcond;
             break;
 
           case NSH_PARSER_ELSE:
-            ret = np->np_st[np->np_ndx].ns_ifcond;
+            ret = np->np_iestate[np->np_iendx].ie_ifcond;
             break;
         }
     }
@@ -1367,13 +1367,13 @@ static bool nsh_cmdenabled(FAR struct nsh_vtbl_s *vtbl)
 static int nsh_ifthenelse(FAR struct nsh_vtbl_s *vtbl, FAR char **ppcmd,
                           FAR char **saveptr, FAR NSH_MEMLIST_TYPE *memlist)
 {
-  struct nsh_parser_s *np = &vtbl->np;
+  FAR struct nsh_parser_s *np = &vtbl->np;
   FAR char *cmd = *ppcmd;
   bool disabled;
 
   if (cmd)
     {
-      /* Check if the command is preceeded by "if" */
+      /* Check if the command is preceded by "if" */
 
       if (strcmp(cmd, "if") == 0)
         {
@@ -1388,9 +1388,9 @@ static int nsh_ifthenelse(FAR struct nsh_vtbl_s *vtbl, FAR char **ppcmd,
 
           /* Verify that "if" is valid in this context */
 
-          if (np->np_st[np->np_ndx].ns_state != NSH_PARSER_NORMAL &&
-              np->np_st[np->np_ndx].ns_state != NSH_PARSER_THEN &&
-              np->np_st[np->np_ndx].ns_state != NSH_PARSER_ELSE)
+          if (np->np_iestate[np->np_iendx].ie_state != NSH_PARSER_NORMAL &&
+              np->np_iestate[np->np_iendx].ie_state != NSH_PARSER_THEN &&
+              np->np_iestate[np->np_iendx].ie_state != NSH_PARSER_ELSE)
             {
               nsh_output(vtbl, g_fmtcontext, "if");
               goto errout;
@@ -1398,7 +1398,7 @@ static int nsh_ifthenelse(FAR struct nsh_vtbl_s *vtbl, FAR char **ppcmd,
 
           /* Check if we have exceeded the maximum depth of nesting */
 
-          if (np->np_ndx >= CONFIG_NSH_NESTDEPTH-1)
+          if (np->np_iendx >= CONFIG_NSH_NESTDEPTH-1)
             {
               nsh_output(vtbl, g_fmtdeepnesting, "if");
               goto errout;
@@ -1406,12 +1406,15 @@ static int nsh_ifthenelse(FAR struct nsh_vtbl_s *vtbl, FAR char **ppcmd,
 
           /* "Push" the old state and set the new state */
 
-          disabled                          = !nsh_cmdenabled(vtbl);
-          np->np_ndx++;
-          np->np_st[np->np_ndx].ns_state    = NSH_PARSER_IF;
-          np->np_st[np->np_ndx].ns_disabled = disabled;
-          np->np_st[np->np_ndx].ns_ifcond   = false;
+          disabled                                 = !nsh_cmdenabled(vtbl);
+          np->np_iendx++;
+          np->np_iestate[np->np_iendx].ie_state    = NSH_PARSER_IF;
+          np->np_iestate[np->np_iendx].ie_disabled = disabled;
+          np->np_iestate[np->np_iendx].ie_ifcond   = false;
         }
+
+      /* Check if the command is "then" */
+
       else if (strcmp(cmd, "then") == 0)
         {
           /* Get the cmd following the then -- there shouldn't be one */
@@ -1425,13 +1428,17 @@ static int nsh_ifthenelse(FAR struct nsh_vtbl_s *vtbl, FAR char **ppcmd,
 
           /* Verify that "then" is valid in this context */
 
-          if (np->np_st[np->np_ndx].ns_state != NSH_PARSER_IF)
+          if (np->np_iestate[np->np_iendx].ie_state != NSH_PARSER_IF)
             {
               nsh_output(vtbl, g_fmtcontext, "then");
               goto errout;
             }
-          np->np_st[np->np_ndx].ns_state = NSH_PARSER_THEN;
+
+          np->np_iestate[np->np_iendx].ie_state = NSH_PARSER_THEN;
         }
+
+      /* Check if the command is "else" */
+
       else if (strcmp(cmd, "else") == 0)
         {
           /* Get the cmd following the else -- there shouldn't be one */
@@ -1443,15 +1450,19 @@ static int nsh_ifthenelse(FAR struct nsh_vtbl_s *vtbl, FAR char **ppcmd,
               goto errout;
             }
 
-          /* Verify that "then" is valid in this context */
+          /* Verify that "else" is valid in this context */
 
-          if (np->np_st[np->np_ndx].ns_state != NSH_PARSER_THEN)
+          if (np->np_iestate[np->np_iendx].ie_state != NSH_PARSER_THEN)
             {
               nsh_output(vtbl, g_fmtcontext, "else");
               goto errout;
             }
-          np->np_st[np->np_ndx].ns_state = NSH_PARSER_ELSE;
+
+          np->np_iestate[np->np_iendx].ie_state = NSH_PARSER_ELSE;
         }
+
+      /* Check if the command is "fi" */
+
       else if (strcmp(cmd, "fi") == 0)
         {
           /* Get the cmd following the fi -- there should be one */
@@ -1465,14 +1476,14 @@ static int nsh_ifthenelse(FAR struct nsh_vtbl_s *vtbl, FAR char **ppcmd,
 
           /* Verify that "fi" is valid in this context */
 
-          if (np->np_st[np->np_ndx].ns_state != NSH_PARSER_THEN &&
-              np->np_st[np->np_ndx].ns_state != NSH_PARSER_ELSE)
+          if (np->np_iestate[np->np_iendx].ie_state != NSH_PARSER_THEN &&
+              np->np_iestate[np->np_iendx].ie_state != NSH_PARSER_ELSE)
             {
               nsh_output(vtbl, g_fmtcontext, "fi");
               goto errout;
             }
 
-          if (np->np_ndx < 1) /* Shouldn't happen */
+          if (np->np_iendx < 1) /* Shouldn't happen */
             {
               nsh_output(vtbl, g_fmtinternalerror, "if");
               goto errout;
@@ -1480,21 +1491,25 @@ static int nsh_ifthenelse(FAR struct nsh_vtbl_s *vtbl, FAR char **ppcmd,
 
           /* "Pop" the previous state */
 
-          np->np_ndx--;
+          np->np_iendx--;
         }
-      else if (np->np_st[np->np_ndx].ns_state == NSH_PARSER_IF)
+
+      /* If we just parsed 'if', then nothing is acceptable other than 'then' */
+
+      else if (np->np_iestate[np->np_iendx].ie_state == NSH_PARSER_IF)
         {
           nsh_output(vtbl, g_fmtcontext, cmd);
           goto errout;
         }
     }
+
   return OK;
 
 errout:
-  np->np_ndx               = 0;
-  np->np_st[0].ns_state    = NSH_PARSER_NORMAL;
-  np->np_st[0].ns_disabled = false;
-  np->np_st[0].ns_ifcond   = false;
+  np->np_iendx                  = 0;
+  np->np_iestate[0].ie_state    = NSH_PARSER_NORMAL;
+  np->np_iestate[0].ie_disabled = false;
+  np->np_iestate[0].ie_ifcond   = false;
   return ERROR;
 }
 #endif
diff --git a/apps/nshlib/nsh_script.c b/apps/nshlib/nsh_script.c
index 3aa698b31..088df6878 100644
--- a/apps/nshlib/nsh_script.c
+++ b/apps/nshlib/nsh_script.c
@@ -83,10 +83,10 @@
 int nsh_script(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
                FAR const char *path)
 {
-  char *fullpath;
-  FILE *stream;
-  char *buffer;
-  char *pret;
+  FAR char *fullpath;
+  FAR FILE *savestream;
+  FAR char *buffer;
+  FAR char *pret;
   int ret = ERROR;
 
   /* The path to the script may be relative to the current working directory */
@@ -102,13 +102,24 @@ int nsh_script(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
   buffer = nsh_linebuffer(vtbl);
   if (buffer)
     {
+      /* Save the parent stream in case of nested script processing */
+
+      savestream = vtbl->np.np_stream;
+
       /* Open the file containing the script */
 
-      stream = fopen(fullpath, "r");
-      if (!stream)
+      vtbl->np.np_stream = fopen(fullpath, "r");
+      if (!vtbl->np.np_stream)
         {
           nsh_output(vtbl, g_fmtcmdfailed, cmd, "fopen", NSH_ERRNO);
+
+          /* Free the allocated path */
+
           nsh_freefullpath(fullpath);
+
+          /* Restore the parent script stream */
+
+          vtbl->np.np_stream = savestream;
           return ERROR;
         }
 
@@ -121,7 +132,7 @@ int nsh_script(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
           /* Get the next line of input from the file */
 
           fflush(stdout);
-          pret = fgets(buffer, CONFIG_NSH_LINELEN, stream);
+          pret = fgets(buffer, CONFIG_NSH_LINELEN, vtbl->np.np_stream);
           if (pret)
             {
               /* Parse process the command.  NOTE:  this is recursive...
@@ -133,9 +144,18 @@ int nsh_script(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
             }
         }
       while (pret && ret == OK);
-      fclose(stream);
+
+      /* Close the script file */
+
+      fclose(vtbl->np.np_stream);
+
+      /* Restore the parent script stream */
+
+      vtbl->np.np_stream = savestream;
     }
 
+  /* Free the allocated path */
+
   nsh_freefullpath(fullpath);
   return ret;
 }