Add memcached_exist()

[awesomized/libmemcached] / libmemcached / exist.cc

diff --git a/libmemcached/exist.cc b/libmemcached/exist.cc
new file mode 100644 (file)
index 0000000..b8d4b0d
--- /dev/null
+++ b/libmemcached/exist.cc
@@ -0,0 +1,149 @@
+/*  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
+ * 
+ *  Libmemcached library
+ *
+ *  Copyright (C) 2011 Data Differential, http://datadifferential.com/
+ *
+ *  Redistribution and use in source and binary forms, with or without
+ *  modification, are permitted provided that the following conditions are
+ *  met:
+ *
+ *      * Redistributions of source code must retain the above copyright
+ *  notice, this list of conditions and the following disclaimer.
+ *
+ *      * Redistributions in binary form must reproduce the above
+ *  copyright notice, this list of conditions and the following disclaimer
+ *  in the documentation and/or other materials provided with the
+ *  distribution.
+ *
+ *      * The names of its contributors may not be used to endorse or
+ *  promote products derived from this software without specific prior
+ *  written permission.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <libmemcached/common.h>
+
+static memcached_return_t ascii_exist(memcached_st *memc, memcached_server_write_instance_st instance, const char *key, size_t key_length)
+{
+  struct libmemcached_io_vector_st vector[]=
+  {
+    { sizeof("add ") -1, "add " },
+    { memcached_array_size(memc->_namespace), memcached_array_string(memc->_namespace) },
+    { key_length, key },
+    { sizeof(" 0") -1, " 0" },
+    { sizeof(" 2678400") -1, " 2678400" },
+    { sizeof(" 0") -1, " 0" },
+    { 2, "\r\n" },
+    { 2, "\r\n" }
+  };
+
+  /* Send command header */
+  memcached_return_t rc=  memcached_vdo(instance, vector, 8, true);
+  if (rc == MEMCACHED_SUCCESS)
+  {
+    char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
+    rc= memcached_response(instance, buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, NULL);
+
+    if (rc == MEMCACHED_NOTSTORED)
+      rc= MEMCACHED_SUCCESS;
+
+    if (rc == MEMCACHED_STORED)
+      rc= MEMCACHED_NOTFOUND;
+  }
+
+  if (rc == MEMCACHED_WRITE_FAILURE)
+    memcached_io_reset(instance);
+
+  return rc;
+}
+
+static memcached_return_t binary_exist(memcached_st *memc, memcached_server_write_instance_st instance, const char *key, size_t key_length)
+{
+  protocol_binary_request_set request= {};
+  size_t send_length= sizeof(request.bytes);
+
+  request.message.header.request.magic= PROTOCOL_BINARY_REQ;
+  request.message.header.request.opcode= PROTOCOL_BINARY_CMD_ADD;
+  request.message.header.request.keylen= htons((uint16_t)(key_length + memcached_array_size(memc->_namespace)));
+  request.message.header.request.datatype= PROTOCOL_BINARY_RAW_BYTES;
+  request.message.header.request.extlen= 8;
+  request.message.body.flags= 0;
+  request.message.body.expiration= htonl(2678400);
+
+  request.message.header.request.bodylen= htonl((uint32_t) (key_length 
+                                                            +memcached_array_size(memc->_namespace)
+                                                            +request.message.header.request.extlen));
+
+  struct libmemcached_io_vector_st vector[]=
+  {
+    { send_length, request.bytes },
+    { memcached_array_size(memc->_namespace), memcached_array_string(memc->_namespace) },
+    { key_length, key }
+  };
+
+  /* write the header */
+  memcached_return_t rc;
+  if ((rc= memcached_vdo(instance, vector, 3, true)) != MEMCACHED_SUCCESS)
+  {
+    memcached_io_reset(instance);
+    return (rc == MEMCACHED_SUCCESS) ? MEMCACHED_WRITE_FAILURE : rc;
+  }
+
+  rc= memcached_response(instance, NULL, 0, NULL);
+
+  if (rc == MEMCACHED_SUCCESS)
+    rc= MEMCACHED_NOTFOUND;
+
+  if (rc == MEMCACHED_DATA_EXISTS)
+    rc= MEMCACHED_SUCCESS;
+
+  return rc;
+}
+
+memcached_return_t memcached_exist(memcached_st *memc, const char *key, size_t key_length)
+{
+  return memcached_exist_by_key(memc, key, key_length, key, key_length);
+}
+
+memcached_return_t memcached_exist_by_key(memcached_st *memc,
+                                          const char *group_key, size_t group_key_length,
+                                          const char *key, size_t key_length)
+{
+  memcached_return_t rc;
+  if (memcached_failed(rc= initialize_query(memc)))
+  {
+    return rc;
+  }
+
+  if (memc->flags.use_udp)
+  {
+    return MEMCACHED_NOT_SUPPORTED;
+  }
+
+
+  uint32_t server_key= memcached_generate_hash_with_redistribution(memc, group_key, group_key_length);
+  memcached_server_write_instance_st instance;
+  instance= memcached_server_instance_fetch(memc, server_key);
+
+  if (memc->flags.binary_protocol)
+  {
+    return binary_exist(memc, instance, key, key_length);
+  }
+  else
+  {
+    return ascii_exist(memc, instance, key, key_length);
+  }
+}