alias expansion, cvar expansion: support optional arguments

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@11610 d7cf8633-e32d-0410-b094-e92efae38249
::stable-branch::merge=afeadf14a66bf63e0188fb3c36c1667a524cc375

diff --git a/cmd.c b/cmd.c
index 0a42ca4a093d2ad9d59882ea45e6a78d52114efc..51e946b299b54248eb2dea7c963cf401891f2516 100644 (file)
--- a/cmd.c
+++ b/cmd.c
@@ -275,7 +275,7 @@ static void Cbuf_Execute_Deferred (void)
 Cbuf_Execute
 ============
 */
-static void Cmd_PreprocessString( const char *intext, char *outtext, unsigned maxoutlen, cmdalias_t *alias );
+static qboolean Cmd_PreprocessString( const char *intext, char *outtext, unsigned maxoutlen, cmdalias_t *alias );
 void Cbuf_Execute (void)
 {
        int i;
@@ -360,8 +360,8 @@ void Cbuf_Execute (void)
                        (strncmp(firstchar, "in_bind", 7) || !ISWHITESPACE(firstchar[7]))
                )
                {
-                       Cmd_PreprocessString( line, preprocessed, sizeof(preprocessed), NULL );
-                       Cmd_ExecuteString (preprocessed, src_command, false);
+                       if(Cmd_PreprocessString( line, preprocessed, sizeof(preprocessed), NULL ))
+                               Cmd_ExecuteString (preprocessed, src_command, false);
                }
                else
                {
@@ -920,9 +920,11 @@ static const char *Cmd_GetCvarValue(const char *var, size_t varlen, cmdalias_t *
 {
        static char varname[MAX_INPUTLINE]; // cmd_mutex
        static char varval[MAX_INPUTLINE]; // cmd_mutex
-       const char *varstr;
+       const char *varstr = NULL;
        char *varfunc;
-static char asis[] = "asis"; // just to suppress const char warnings
+       qboolean required = false;
+       qboolean optional = false;
+       static char asis[] = "asis"; // just to suppress const char warnings
 
        if(varlen >= MAX_INPUTLINE)
                varlen = MAX_INPUTLINE - 1;
@@ -939,10 +941,34 @@ static char asis[] = "asis"; // just to suppress const char warnings
        if(*var == 0)
        {
                // empty cvar name?
-               return NULL;
+               if(alias)
+                       Con_Printf("Warning: Could not expand $ in alias %s\n", alias->name);
+               else
+                       Con_Printf("Warning: Could not expand $\n");
+               return "$";
        }
 
-       varstr = NULL;
+       if(varfunc)
+       {
+               char *p;
+               // ? means optional
+               while((p = strchr(varfunc, '?')))
+               {
+                       optional = true;
+                       memmove(p, p+1, strlen(p)); // with final NUL
+               }
+               // ! means required
+               while((p = strchr(varfunc, '!')))
+               {
+                       required = true;
+                       memmove(p, p+1, strlen(p)); // with final NUL
+               }
+               // kill spaces
+               while((p = strchr(varfunc, ' ')))
+               {
+                       memmove(p, p+1, strlen(p)); // with final NUL
+               }
+       }
 
        if(varname[0] == '$')
                varstr = Cmd_GetDirectCvarValue(Cmd_GetDirectCvarValue(varname + 1, alias, NULL), alias, NULL);
@@ -958,11 +984,27 @@ static char asis[] = "asis"; // just to suppress const char warnings
 
        if(!varstr)
        {
-               if(alias)
-                       Con_Printf("Warning: Could not expand $%s in alias %s\n", varname, alias->name);
+               if(required)
+               {
+                       if(alias)
+                               Con_Printf("Error: Could not expand $%s in alias %s\n", varname, alias->name);
+                       else
+                               Con_Printf("Error: Could not expand $%s\n", varname);
+                       return NULL;
+               }
+               else if(optional)
+               {
+                       return "";
+               }
                else
-                       Con_Printf("Warning: Could not expand $%s\n", varname);
-               return NULL;
+               {
+                       if(alias)
+                               Con_Printf("Warning: Could not expand $%s in alias %s\n", varname, alias->name);
+                       else
+                               Con_Printf("Warning: Could not expand $%s\n", varname);
+                       dpsnprintf(varval, sizeof(varval), "$%s", varname);
+                       return varval;
+               }
        }
 
        if(!varfunc || !strcmp(varfunc, "q")) // note: quoted form is default, use "asis" to override!
@@ -987,7 +1029,7 @@ Cmd_PreprocessString
 
 Preprocesses strings and replaces $*, $param#, $cvar accordingly. Also strips comments.
 */
-static void Cmd_PreprocessString( const char *intext, char *outtext, unsigned maxoutlen, cmdalias_t *alias ) {
+static qboolean Cmd_PreprocessString( const char *intext, char *outtext, unsigned maxoutlen, cmdalias_t *alias ) {
        const char *in;
        size_t eat, varlen;
        unsigned outlen;
@@ -995,7 +1037,7 @@ static void Cmd_PreprocessString( const char *intext, char *outtext, unsigned ma
 
        // don't crash if there's no room in the outtext buffer
        if( maxoutlen == 0 ) {
-               return;
+               return false;
        }
        maxoutlen--; // because of \0
 
@@ -1016,6 +1058,10 @@ static void Cmd_PreprocessString( const char *intext, char *outtext, unsigned ma
                        //   that way)
                        // - ${var asis} inserts the cvar value as is, without doing this
                        //   quoting
+                       // - ${var ?} silently expands to the empty string if
+                       //   $var does not exist
+                       // - ${var !} fails expansion and executes nothing if
+                       //   $var does not exist
                        // - prefix the cvar name with a dollar sign to do indirection;
                        //   for example, if $x has the value timelimit, ${$x} will return
                        //   the value of $timelimit
@@ -1026,6 +1072,7 @@ static void Cmd_PreprocessString( const char *intext, char *outtext, unsigned ma
                        //   parameters, without extra quoting, so one can use $* to just
                        //   pass all parameters around. All parameters starting from $n
                        //   can be referred to as $n- (so $* is equivalent to $1-).
+                       // - ${* q} and ${n- q} force quoting anyway
                        //
                        // Note: when expanding an alias, cvar expansion is done in the SAME step
                        // as alias expansion so that alias parameters or cvar values containing
@@ -1062,6 +1109,8 @@ static void Cmd_PreprocessString( const char *intext, char *outtext, unsigned ma
                                if(in[varlen + 1] == '}')
                                {
                                        val = Cmd_GetCvarValue(in + 1, varlen, alias);
+                                       if(!val)
+                                               return false;
                                        eat = varlen + 2;
                                }
                                else
@@ -1073,6 +1122,8 @@ static void Cmd_PreprocessString( const char *intext, char *outtext, unsigned ma
                        } else {
                                varlen = strspn(in, "#*0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_-");
                                val = Cmd_GetCvarValue(in, varlen, alias);
+                               if(!val)
+                                       return false;
                                eat = varlen;
                        }
                        if(val)
@@ -1097,6 +1148,7 @@ static void Cmd_PreprocessString( const char *intext, char *outtext, unsigned ma
                        outtext[outlen++] = *in++;
        }
        outtext[outlen] = 0;
+       return true;
 }
 
 /*
@@ -1110,7 +1162,9 @@ static void Cmd_ExecuteAlias (cmdalias_t *alias)
 {
        static char buffer[ MAX_INPUTLINE ]; // cmd_mutex
        static char buffer2[ MAX_INPUTLINE ]; // cmd_mutex
-       Cmd_PreprocessString( alias->value, buffer, sizeof(buffer) - 2, alias );
+       qboolean ret = Cmd_PreprocessString( alias->value, buffer, sizeof(buffer) - 2, alias );
+       if(!ret)
+               return;
        // insert at start of command buffer, so that aliases execute in order
        // (fixes bug introduced by Black on 20050705)