Refactor of async code. poll() is now only called when needed.
[awesomized/libmemcached] / lib / memcached_io.c
index 2f86930e3690f482c34a2fd7c523ba4d2c316677..daf64755c69ce171234c4c026aee925009aad9eb 100644 (file)
 #include "common.h"
 #include "memcached_io.h"
 #include <sys/select.h>
+#include <poll.h>
 
-ssize_t memcached_io_read(memcached_st *ptr, unsigned  int server_key,
-                          char *buffer, size_t length)
-{
-  size_t x;
-  char *buffer_ptr;
+typedef enum {
+  MEM_READ,
+  MEM_WRITE,
+} memc_read_or_write;
 
-  buffer_ptr= buffer;
+static ssize_t io_flush(memcached_st *ptr, unsigned int server_key, 
+                                  memcached_return *error);
 
-  for (x= 0, buffer_ptr= buffer; 
-       x < length; x++)
-  {
-    if (!ptr->read_buffer_length)
-    {
-      if (length > 1)
-      {
+static memcached_return io_wait(memcached_st *ptr, unsigned int server_key, 
+                                memc_read_or_write read_or_write)
+{
+  struct pollfd fds[1];
+  short flags= 0;
+  int error;
 
-        size_t data_read;
-        data_read= recv(ptr->hosts[server_key].fd, 
-                        buffer_ptr, 
-                        length - x, 0);
-        if (data_read == -1)
-        {
-          return -1;
-        }
-        if (data_read == 0)
-          return x;
+  if (read_or_write == MEM_WRITE) /* write */
+    flags= POLLOUT |  POLLERR;
+  else
+    flags= POLLIN | POLLERR;
 
-        data_read+= x;
+  memset(&fds, 0, sizeof(struct pollfd));
+  fds[0].fd= ptr->hosts[server_key].fd;
+  fds[0].events= flags;
 
-        return data_read;
-      }
-      else
-      {
-        size_t data_read;
-try_again:
+  error= poll(fds, 1, ptr->poll_timeout);
 
-        if (ptr->flags & MEM_NO_BLOCK)
-        {
-          struct timeval local_tv;
-          fd_set set;
+  if (error == 1)
+    return MEMCACHED_SUCCESS;
+  else if (error == 0)
+  {
+    WATCHPOINT_NUMBER(read_or_write);
+    return MEMCACHED_TIMEOUT;
+  }
 
-          memset(&local_tv, 0, sizeof(struct timeval));
+  WATCHPOINT;
+  /* Imposssible for anything other then -1 */
+  WATCHPOINT_ASSERT(error == -1);
+  memcached_quit_server(ptr, server_key, 1);
+  return MEMCACHED_FAILURE;
 
-          local_tv.tv_sec= 0;
-          local_tv.tv_usec= 300;
+}
 
-          FD_ZERO(&set);
-          FD_SET(ptr->hosts[server_key].fd, &set);
+ssize_t memcached_io_read(memcached_st *ptr, unsigned  int server_key,
+                          char *buffer, size_t length)
+{
+  char *buffer_ptr;
 
-          select(1, &set, NULL, NULL, &local_tv);
-        }
+  buffer_ptr= buffer;
+
+  while (length)
+  {
+    if (!ptr->hosts[server_key].read_buffer_length)
+    {
+      size_t data_read;
 
-        data_read= recv(ptr->hosts[server_key].fd, 
-                        ptr->read_buffer, 
-                        MEMCACHED_MAX_BUFFER, 0);
+      while (1)
+      {
+        data_read= read(ptr->hosts[server_key].fd, 
+                        ptr->hosts[server_key].read_buffer, 
+                        MEMCACHED_MAX_BUFFER);
         if (data_read == -1)
         {
-          if (errno == EAGAIN)
-            goto try_again;
-          return -1;
+          switch (errno)
+          {
+          case EAGAIN:
+            {
+              memcached_return rc;
+              rc= io_wait(ptr, server_key, MEM_READ);
+
+              if (rc == MEMCACHED_SUCCESS)
+                continue;
+
+              memcached_quit_server(ptr, server_key, 1);
+              return -1;
+            }
+          default:
+            {
+              memcached_quit_server(ptr, server_key, 1);
+              ptr->cached_errno= errno;
+              return -1;
+            }
+          }
         }
-        ptr->read_buffer_length= data_read;
-        ptr->read_ptr= ptr->read_buffer;
+        else if (data_read)
+          break;
+        /* If zero, just keep looping */
       }
 
-      if (ptr->read_buffer_length == -1)
-        return -1;
-      if (ptr->read_buffer_length == 0)
-        return x;
+      ptr->hosts[server_key].read_buffer_length= data_read;
+      ptr->hosts[server_key].read_ptr= ptr->hosts[server_key].read_buffer;
     }
-    *buffer_ptr= *ptr->read_ptr;
+
+    *buffer_ptr= *ptr->hosts[server_key].read_ptr;
+    length--;
+    ptr->hosts[server_key].read_ptr++;
+    ptr->hosts[server_key].read_buffer_length--;
     buffer_ptr++;
-    ptr->read_ptr++;
-    ptr->read_buffer_length--;
   }
 
-  return length;
+  return (size_t)(buffer_ptr - buffer);
 }
 
 ssize_t memcached_io_write(memcached_st *ptr, unsigned int server_key,
@@ -92,97 +116,136 @@ ssize_t memcached_io_write(memcached_st *ptr, unsigned int server_key,
 
   for (x= 0; x < length; x++)
   {
-    ptr->write_buffer[ptr->write_buffer_offset]= buffer[x];
-    ptr->write_buffer_offset++;
-
-    if (ptr->write_buffer_offset == MEMCACHED_MAX_BUFFER)
+    if (ptr->hosts[server_key].write_ptr == 0)
+      ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
+    WATCHPOINT_ASSERT(ptr->hosts[server_key].write_ptr);
+    *ptr->hosts[server_key].write_ptr= buffer[x];
+    ptr->hosts[server_key].write_ptr++;
+    ptr->hosts[server_key].write_buffer_offset++;
+
+    if (ptr->hosts[server_key].write_buffer_offset == MEMCACHED_MAX_BUFFER)
     {
+      memcached_return rc;
       size_t sent_length;
 
-      sent_length= memcached_io_flush(ptr, server_key);
+      sent_length= io_flush(ptr, server_key, &rc);
+      if (sent_length == -1)
+        return -1;
 
-      assert(sent_length == MEMCACHED_MAX_BUFFER);
-      ptr->write_buffer_offset= 0;
+      WATCHPOINT_ASSERT(sent_length == MEMCACHED_MAX_BUFFER);
+      ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
+      ptr->hosts[server_key].write_buffer_offset= 0;
     }
   }
 
   if (with_flush)
   {
-    if (memcached_io_flush(ptr, server_key) == -1)
+    memcached_return rc;
+    if (io_flush(ptr, server_key, &rc) == -1)
       return -1;
   }
 
   return length;
 }
 
-ssize_t memcached_io_flush(memcached_st *ptr, unsigned int server_key)
+memcached_return memcached_io_close(memcached_st *ptr, unsigned int server_key)
 {
-  size_t sent_length;
-  char *write_ptr= ptr->write_buffer;
-  size_t write_length= ptr->write_buffer_offset;
-  unsigned int loop= 1;
+  memcached_return rc;
 
-  if (ptr->write_buffer_offset == 0)
-    return 0;
-
-  while (write_length)
+  rc= MEMCACHED_SUCCESS;
+  if (ptr->flags & MEM_NO_BLOCK)
   {
-    if (ptr->flags & MEM_NO_BLOCK)
+    int error;
+    struct pollfd fds[1];
+    short flags= 0;
+
+    flags= POLLHUP |  POLLERR;
+
+    memset(&fds, 0, sizeof(struct pollfd));
+    fds[0].fd= ptr->hosts[server_key].fd;
+    fds[0].events= flags;
+    fds[0].revents= 0;
+
+    error= poll(fds, 1, ptr->poll_timeout == -1 ? 100 : ptr->poll_timeout);
+
+    if (error == -1)
     {
+      memcached_quit_server(ptr, server_key, 1);
+      return MEMCACHED_FAILURE;
+    }
+    else if (error == 0)
+      return MEMCACHED_FAILURE; /* Timeout occurred */
+  }
 
-      while (1)
-      {
-        struct timeval local_tv;
-        fd_set set;
-        int select_return;
+  close(ptr->hosts[server_key].fd);
 
-        local_tv.tv_sec= 0;
-        local_tv.tv_usec= 300 * loop;
+  return rc;
+}
 
-        FD_ZERO(&set);
-        FD_SET(ptr->hosts[server_key].fd, &set);
+static ssize_t io_flush(memcached_st *ptr, unsigned int server_key, 
+                                  memcached_return *error)
+{
+  size_t sent_length;
+  size_t return_length;
+  char *write_ptr= ptr->hosts[server_key].write_buffer;
+  size_t write_length= ptr->hosts[server_key].write_buffer_offset;
 
-        select_return= select(1, NULL, &set, NULL, &local_tv);
+  *error= MEMCACHED_SUCCESS;
 
-        if (select_return == -1)
-        {
-          ptr->my_errno= errno;
-          return -1;
-        }
-        else if (!select_return)
-          break;
-      }
-    }
+  if (ptr->hosts[server_key].write_buffer_offset == 0)
+    return 0;
 
+  return_length= 0;
+  while (write_length)
+  {
     sent_length= 0;
-    if ((sent_length= send(ptr->hosts[server_key].fd, write_ptr, 
-                           write_length, 0)) == -1)
+    if (ptr->hosts[server_key].type == MEMCACHED_CONNECTION_UDP)
     {
-      switch (errno)
+      sent_length= sendto(ptr->hosts[server_key].fd, 
+                          write_ptr, write_length, 0, 
+                          (struct sockaddr *)&ptr->hosts[server_key].address_info->ai_addr, 
+                          sizeof(struct sockaddr));
+    }
+    else
+    {
+      if ((ssize_t)(sent_length= write(ptr->hosts[server_key].fd, write_ptr, 
+                                       write_length)) == -1)
       {
-      case ENOBUFS:
-      case EAGAIN:
-        if (loop < 10)
+        switch (errno)
         {
-          loop++;
-          break;
+        case ENOBUFS:
+          continue;
+        case EAGAIN:
+          {
+            memcached_return rc;
+            rc= io_wait(ptr, server_key, MEM_WRITE);
+
+            if (rc == MEMCACHED_SUCCESS)
+              continue;
+
+            memcached_quit_server(ptr, server_key, 1);
+            return -1;
+          }
+        default:
+          memcached_quit_server(ptr, server_key, 1);
+          ptr->cached_errno= errno;
+          *error= MEMCACHED_ERRNO;
+          return -1;
         }
-        /* Yes, we want to fall through */
-      default:
-        ptr->my_errno= errno;
-        return -1;
       }
     }
-    else
-    {
-      write_ptr+= sent_length;
-      write_length-= sent_length;
-    }
+
+    write_ptr+= sent_length;
+    write_length-= sent_length;
+    return_length+= sent_length;
   }
 
-  ptr->write_buffer_offset= 0;
+  WATCHPOINT_ASSERT(write_length == 0);
+  WATCHPOINT_ASSERT(return_length == ptr->hosts[server_key].write_buffer_offset);
+  ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
+  ptr->hosts[server_key].write_buffer_offset= 0;
 
-  return sent_length;
+  return return_length;
 }
 
 /* 
@@ -190,6 +253,7 @@ ssize_t memcached_io_flush(memcached_st *ptr, unsigned int server_key)
 */
 void memcached_io_reset(memcached_st *ptr, unsigned int server_key)
 {
-  ptr->write_buffer_offset= 0;
+  ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
+  ptr->hosts[server_key].write_buffer_offset= 0;
   memcached_quit(ptr);
 }