synchronous I/O networking functions originally used just for replication refactored in a file as generally useful, they are used in the cluster branch for MIGRATE.

src/syncio.c

@@ -0,0 +1,98 @@
+/* Synchronous socket I/O operations, with timeouts.
+ * Redis performs most of the I/O in a nonblocking way, with the exception
+ * of the SYNC command where the slave does it in a blocking way, and
+ * the MIGRATE command that must be blocking in order to be atomic from the
+ * point of view of the two instances (one migrating the key and one receiving
+ * the key). This is why need the following blocking I/O functions.
+ *
+ * Copyright (c) 2009-2010, Salvatore Sanfilippo <antirez at gmail dot com>
+ * All rights reserved.
+ *
+ * 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.
+ *   * Neither the name of Redis nor the names of its contributors may 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 "redis.h"
+
+int syncWrite(int fd, char *ptr, ssize_t size, int timeout) {
+    ssize_t nwritten, ret = size;
+    time_t start = time(NULL);
+
+    timeout++;
+    while(size) {
+        if (aeWait(fd,AE_WRITABLE,1000) & AE_WRITABLE) {
+            nwritten = write(fd,ptr,size);
+            if (nwritten == -1) return -1;
+            ptr += nwritten;
+            size -= nwritten;
+        }
+        if ((time(NULL)-start) > timeout) {
+            errno = ETIMEDOUT;
+            return -1;
+        }
+    }
+    return ret;
+}
+
+int syncRead(int fd, char *ptr, ssize_t size, int timeout) {
+    ssize_t nread, totread = 0;
+    time_t start = time(NULL);
+
+    timeout++;
+    while(size) {
+        if (aeWait(fd,AE_READABLE,1000) & AE_READABLE) {
+            nread = read(fd,ptr,size);
+            if (nread <= 0) return -1;
+            ptr += nread;
+            size -= nread;
+            totread += nread;
+        }
+        if ((time(NULL)-start) > timeout) {
+            errno = ETIMEDOUT;
+            return -1;
+        }
+    }
+    return totread;
+}
+
+int syncReadLine(int fd, char *ptr, ssize_t size, int timeout) {
+    ssize_t nread = 0;
+
+    size--;
+    while(size) {
+        char c;
+
+        if (syncRead(fd,&c,1,timeout) == -1) return -1;
+        if (c == '\n') {
+            *ptr = '\0';
+            if (nread && *(ptr-1) == '\r') *(ptr-1) = '\0';
+            return nread;
+        } else {
+            *ptr++ = c;
+            *ptr = '\0';
+            nread++;
+        }
+    }
+    return nread;
+}