Merge remote-tracking branch 'upstream/unstable' into help_subcommands

src/scripting.c

@@ -1141,18 +1141,38 @@ int redis_math_randomseed (lua_State *L) {
  * EVAL and SCRIPT commands implementation
  * ------------------------------------------------------------------------- */
 
-/* Define a lua function with the specified function name and body.
- * The function name musts be a 42 characters long string, since all the
- * functions we defined in the Lua context are in the form:
+/* Define a Lua function with the specified body.
+ * The function name will be generated in the following form:
  *
  *   f_<hex sha1 sum>
  *
- * On success C_OK is returned, and nothing is left on the Lua stack.
- * On error C_ERR is returned and an appropriate error is set in the
- * client context. */
-int luaCreateFunction(client *c, lua_State *lua, char *funcname, robj *body) {
-    sds funcdef = sdsempty();
+ * The function increments the reference count of the 'body' object as a
+ * side effect of a successful call.
+ *
+ * On success a pointer to an SDS string representing the function SHA1 of the
+ * just added function is returned (and will be valid until the next call
+ * to scriptingReset() function), otherwise NULL is returned.
+ *
+ * The function handles the fact of being called with a script that already
+ * exists, and in such a case, it behaves like in the success case.
+ *
+ * If 'c' is not NULL, on error the client is informed with an appropriate
+ * error describing the nature of the problem and the Lua interpreter error. */
+sds luaCreateFunction(client *c, lua_State *lua, robj *body) {
+    char funcname[43];
+    dictEntry *de;
 
+    funcname[0] = 'f';
+    funcname[1] = '_';
+    sha1hex(funcname+2,body->ptr,sdslen(body->ptr));
+
+    sds sha = sdsnewlen(funcname+2,40);
+    if ((de = dictFind(server.lua_scripts,sha)) != NULL) {
+        sdsfree(sha);
+        return dictGetKey(de);
+    }
+
+    sds funcdef = sdsempty();
     funcdef = sdscat(funcdef,"function ");
     funcdef = sdscatlen(funcdef,funcname,42);
     funcdef = sdscatlen(funcdef,"() ",3);
@@ -1160,30 +1180,35 @@ int luaCreateFunction(client *c, lua_State *lua, char *funcname, robj *body) {
     funcdef = sdscatlen(funcdef,"\nend",4);
 
     if (luaL_loadbuffer(lua,funcdef,sdslen(funcdef),"@user_script")) {
-        addReplyErrorFormat(c,"Error compiling script (new function): %s\n",
-            lua_tostring(lua,-1));
+        if (c != NULL) {
+            addReplyErrorFormat(c,
+                "Error compiling script (new function): %s\n",
+                lua_tostring(lua,-1));
+        }
         lua_pop(lua,1);
+        sdsfree(sha);
         sdsfree(funcdef);
-        return C_ERR;
+        return NULL;
     }
     sdsfree(funcdef);
+
     if (lua_pcall(lua,0,0,0)) {
-        addReplyErrorFormat(c,"Error running script (new function): %s\n",
-            lua_tostring(lua,-1));
+        if (c != NULL) {
+            addReplyErrorFormat(c,"Error running script (new function): %s\n",
+                lua_tostring(lua,-1));
+        }
         lua_pop(lua,1);
-        return C_ERR;
+        sdsfree(sha);
+        return NULL;
     }
 
     /* We also save a SHA1 -> Original script map in a dictionary
      * so that we can replicate / write in the AOF all the
      * EVALSHA commands as EVAL using the original script. */
-    {
-        int retval = dictAdd(server.lua_scripts,
-                             sdsnewlen(funcname+2,40),body);
-        serverAssertWithInfo(c,NULL,retval == DICT_OK);
-        incrRefCount(body);
-    }
-    return C_OK;
+    int retval = dictAdd(server.lua_scripts,sha,body);
+    serverAssertWithInfo(c ? c : server.lua_client,NULL,retval == DICT_OK);
+    incrRefCount(body);
+    return sha;
 }
 
 /* This is the Lua script "count" hook that we use to detect scripts timeout. */
@@ -1282,10 +1307,10 @@ void evalGenericCommand(client *c, int evalsha) {
             addReply(c, shared.noscripterr);
             return;
         }
-        if (luaCreateFunction(c,lua,funcname,c->argv[1]) == C_ERR) {
+        if (luaCreateFunction(c,lua,c->argv[1]) == NULL) {
             lua_pop(lua,1); /* remove the error handler from the stack. */
             /* The error is sent to the client by luaCreateFunction()
-             * itself when it returns C_ERR. */
+             * itself when it returns NULL. */
             return;
         }
         /* Now the following is guaranteed to return non nil */
@@ -1456,22 +1481,9 @@ void scriptCommand(client *c) {
                 addReply(c,shared.czero);
         }
     } else if (c->argc == 3 && !strcasecmp(c->argv[1]->ptr,"load")) {
-        char funcname[43];
-        sds sha;
-
-        funcname[0] = 'f';
-        funcname[1] = '_';
-        sha1hex(funcname+2,c->argv[2]->ptr,sdslen(c->argv[2]->ptr));
-        sha = sdsnewlen(funcname+2,40);
-        if (dictFind(server.lua_scripts,sha) == NULL) {
-            if (luaCreateFunction(c,server.lua,funcname,c->argv[2])
-                    == C_ERR) {
-                sdsfree(sha);
-                return;
-            }
-        }
-        addReplyBulkCBuffer(c,funcname+2,40);
-        sdsfree(sha);
+        sds sha = luaCreateFunction(c,server.lua,c->argv[2]);
+        if (sha == NULL) return; /* The error was sent by luaCreateFunction(). */
+        addReplyBulkCBuffer(c,sha,40);
         forceCommandPropagation(c,PROPAGATE_REPL|PROPAGATE_AOF);
     } else if (c->argc == 2 && !strcasecmp(c->argv[1]->ptr,"kill")) {
         if (server.lua_caller == NULL) {