Index: /trunk/server/memcached.c =================================================================== --- /trunk/server/memcached.c (revision 624) +++ /trunk/server/memcached.c (revision 627) @@ -720,12 +720,53 @@ int stored = 0; + item *new_it = NULL; + int flags; + if (old_it != NULL && comm == NREAD_ADD) { /* add only adds a nonexistent item, but promote to head of LRU */ do_item_update(old_it); - } else if (!old_it && comm == NREAD_REPLACE) { + } else if (!old_it && (comm == NREAD_REPLACE + || comm == NREAD_APPEND || comm == NREAD_PREPEND)) + { /* replace only replaces an existing value; don't store */ - } else if (delete_locked && (comm == NREAD_REPLACE || comm == NREAD_ADD)) { + } else if (delete_locked && (comm == NREAD_REPLACE || comm == NREAD_ADD + || comm == NREAD_APPEND || comm == NREAD_PREPEND)) + { /* replace and add can't override delete locks; don't store */ } else { + + /* + * Append - combine new and old record into single one. Here it's + * atomic and thread-safe. + */ + + if (comm == NREAD_APPEND || comm == NREAD_PREPEND) { + + /* we have it and old_it here - alloc memory to hold both */ + /* flags was already lost - so recover them from ITEM_suffix(it) */ + + flags = (int) strtol(ITEM_suffix(it), (char **) NULL, 10); + + new_it = do_item_alloc(key, it->nkey, flags, it->exptime, it->nbytes + old_it->nbytes - 2 /* CRLF */); + + if (new_it == NULL) { + /* SERVER_ERROR out of memory */ + return 0; + } + + /* copy data from it and old_it to new_it */ + + if (comm == NREAD_APPEND) { + memcpy(ITEM_data(new_it), ITEM_data(old_it), old_it->nbytes); + memcpy(ITEM_data(new_it) + old_it->nbytes - 2 /* CRLF */, ITEM_data(it), it->nbytes); + } else { + /* NREAD_PREPEND */ + memcpy(ITEM_data(new_it), ITEM_data(it), it->nbytes); + memcpy(ITEM_data(new_it) + it->nbytes - 2 /* CRLF */, ITEM_data(old_it), old_it->nbytes); + } + + it = new_it; + } + /* "set" commands can override the delete lock window... in which case we have to find the old hidden item @@ -743,6 +784,9 @@ } - if (old_it) + if (old_it != NULL) do_item_remove(old_it); /* release our reference */ + if (new_it != NULL) + do_item_remove(new_it); + return stored; } @@ -1209,16 +1253,4 @@ } - /* Check if append -- if yes, search for previous entry, and allocate memory for both */ - if( comm == NREAD_APPEND ){ - old_it = assoc_find(key,nkey); - - if( old_it && (old_it->nbytes)>2 ){ // previous must be more than \r\n - old_vlen = old_it->nbytes - 2; - vlen += old_vlen; // append the length of old data - } else { - comm = NREAD_REPLACE; // no old entry: treat as replace - } - } - it = item_alloc(key, nkey, flags, realtime(exptime), vlen+2); @@ -1269,16 +1301,4 @@ c->ritem = ITEM_data(it); c->rlbytes = it->nbytes; - - - /* If append, prepend old data before new - adjust item, rlbytes variables too - * Now that data has been merged, treat simply as a replace command - */ - if (comm == NREAD_APPEND ){ - memcpy( c->ritem, ITEM_data(old_it), old_vlen ); - c->ritem += old_vlen; - c->rlbytes -= old_vlen; - comm = NREAD_REPLACE; - } - c->item_comm = comm; conn_set_state(c, conn_nread); @@ -1515,4 +1535,5 @@ (strcmp(tokens[COMMAND_TOKEN].value, "set") == 0 && (comm = NREAD_SET)) || (strcmp(tokens[COMMAND_TOKEN].value, "replace") == 0 && (comm = NREAD_REPLACE)) || + (strcmp(tokens[COMMAND_TOKEN].value, "prepend") == 0 && (comm = NREAD_PREPEND)) || (strcmp(tokens[COMMAND_TOKEN].value, "append") == 0 && (comm = NREAD_APPEND)) )) { Index: /trunk/server/ChangeLog =================================================================== --- /trunk/server/ChangeLog (revision 624) +++ /trunk/server/ChangeLog (revision 627) @@ -15,5 +15,6 @@ * Add append command support written by Filipe Laborde. - Tests/protocol doc updates by Paul Lindner. + Thread safe version plus prepend command from Maxim Dounin + * The memcached-tool script can now display stats. Patch Index: /trunk/server/memcached.h =================================================================== --- /trunk/server/memcached.h (revision 620) +++ /trunk/server/memcached.h (revision 627) @@ -139,4 +139,5 @@ #define NREAD_REPLACE 3 #define NREAD_APPEND 4 +#define NREAD_PREPEND 5 typedef struct { Index: /trunk/server/doc/protocol.txt =================================================================== --- /trunk/server/doc/protocol.txt (revision 620) +++ /trunk/server/doc/protocol.txt (revision 627) @@ -54,6 +54,6 @@ There are three types of commands. -Storage commands (there are five: "set", "add", "replace", "append" -and "cas") ask the server to store some data identified by a key. The +Storage commands (there are six: "set", "add", "replace", "append" +"prepend" and "cas") ask the server to store some data identified by a key. The client sends a command line, and then a data block; after that the client expects one line of response, which will indicate success or @@ -127,7 +127,7 @@ First, the client sends a command line which looks like this: - []\r\n - -- is "set", "add", "replace", "append", or "cas" + []\r\n + +- is "set", "add", "replace", "append", "prepend", or "cas" "set" means "store this data". @@ -139,5 +139,7 @@ already hold data for this key". - "append" means "add this data to an existing key". + "append" means "add this data to an existing key after existing data". + + "prepend" means "add this data to an existing key before existing data". "cas" is a check and set operation which means "store this data but @@ -166,4 +168,6 @@ - is a unique 64-bit value of an existing entry. + Clients should use the value returned from the "gets" command + when issuing "cas" updates. After this line, the client sends the data block: