* 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. */
+ * the key). This is why need the following blocking I/O functions.
+ *
+ * All the functions take the timeout in milliseconds. */
-int syncWrite(int fd, char *ptr, ssize_t size, int timeout) {
- ssize_t nwritten, ret = size;
- time_t start = time(NULL);
+#define REDIS_SYNCIO_RESOLUTION 10 /* Resolution in milliseconds */
- timeout++;
- while(size) {
- if (aeWait(fd,AE_WRITABLE,1000) & AE_WRITABLE) {
- nwritten = write(fd,ptr,size);
- if (nwritten == -1) return -1;
+/* Write the specified payload to 'fd'. If writing the whole payload will be
+ * done within 'timeout' milliseconds the operation succeeds and 'size' is
+ * returned. Otherwise the operation fails, -1 is returned, and an unspecified
+ * partial write could be performed against the file descriptor. */
+ssize_t syncWrite(int fd, char *ptr, ssize_t size, long long timeout) {
+ ssize_t nwritten, ret = size;
+ long long start = mstime();
+ long long remaining = timeout;
+
+ while(1) {
+ long long wait = (remaining > REDIS_SYNCIO_RESOLUTION) ?
+ remaining : REDIS_SYNCIO_RESOLUTION;
+ long long elapsed;
+
+ /* Optimistically try to write before checking if the file descriptor
+ * is actually writable. At worst we get EAGAIN. */
+ nwritten = write(fd,ptr,size);
+ if (nwritten == -1) {
+ if (errno != EAGAIN) return -1;
+ } else {
ptr += nwritten;
size -= nwritten;
}
- if ((time(NULL)-start) > timeout) {
+ if (size == 0) return ret;
+
+ /* Wait */
+ aeWait(fd,AE_WRITABLE,wait);
+ elapsed = mstime() - start;
+ if (elapsed >= timeout) {
errno = ETIMEDOUT;
return -1;
}
+ remaining = timeout - elapsed;
}
- return ret;
}
-int syncRead(int fd, char *ptr, ssize_t size, int timeout) {
+/* Read the specified amount of bytes from 'fd'. If all the bytes are read
+ * within 'timeout' milliseconds the operation succeed and 'size' is returned.
+ * Otherwise the operation fails, -1 is returned, and an unspecified amount of
+ * data could be read from the file descriptor. */
+ssize_t syncRead(int fd, char *ptr, ssize_t size, long long 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;
+ long long start = mstime();
+ long long remaining = timeout;
+
+ if (size == 0) return 0;
+ while(1) {
+ long long wait = (remaining > REDIS_SYNCIO_RESOLUTION) ?
+ remaining : REDIS_SYNCIO_RESOLUTION;
+ long long elapsed;
+
+ /* Optimistically try to read before checking if the file descriptor
+ * is actually readable. At worst we get EAGAIN. */
+ nread = read(fd,ptr,size);
+ if (nread == 0) return -1; /* short read. */
+ if (nread == -1) {
+ if (errno != EAGAIN) return -1;
+ } else {
ptr += nread;
size -= nread;
totread += nread;
}
- if ((time(NULL)-start) > timeout) {
+ if (size == 0) return totread;
+
+ /* Wait */
+ aeWait(fd,AE_READABLE,wait);
+ elapsed = mstime() - start;
+ if (elapsed >= timeout) {
errno = ETIMEDOUT;
return -1;
}
+ remaining = timeout - elapsed;
}
- return totread;
}
-int syncReadLine(int fd, char *ptr, ssize_t size, int timeout) {
+/* Read a line making sure that every char will not require more than 'timeout'
+ * milliseconds to be read.
+ *
+ * On success the number of bytes read is returned, otherwise -1.
+ * On success the string is always correctly terminated with a 0 byte. */
+ssize_t syncReadLine(int fd, char *ptr, ssize_t size, long long timeout) {
ssize_t nread = 0;
size--;
}
return nread;
}
-
-/* ----------------- Blocking sockets I/O with timeouts --------------------- */
-
-/* Write binary-safe string into a file in the bulkformat
- * $<count>\r\n<payload>\r\n */
-int fwriteBulkString(FILE *fp, char *s, unsigned long len) {
- char cbuf[128];
- int clen;
- cbuf[0] = '$';
- clen = 1+ll2string(cbuf+1,sizeof(cbuf)-1,len);
- cbuf[clen++] = '\r';
- cbuf[clen++] = '\n';
- if (fwrite(cbuf,clen,1,fp) == 0) return 0;
- if (len > 0 && fwrite(s,len,1,fp) == 0) return 0;
- if (fwrite("\r\n",2,1,fp) == 0) return 0;
- return 1;
-}
-
-/* Write a double value in bulk format $<count>\r\n<payload>\r\n */
-int fwriteBulkDouble(FILE *fp, double d) {
- char buf[128], dbuf[128];
-
- snprintf(dbuf,sizeof(dbuf),"%.17g\r\n",d);
- snprintf(buf,sizeof(buf),"$%lu\r\n",(unsigned long)strlen(dbuf)-2);
- if (fwrite(buf,strlen(buf),1,fp) == 0) return 0;
- if (fwrite(dbuf,strlen(dbuf),1,fp) == 0) return 0;
- return 1;
-}
-
-/* Write a long value in bulk format $<count>\r\n<payload>\r\n */
-int fwriteBulkLongLong(FILE *fp, long long l) {
- char bbuf[128], lbuf[128];
- unsigned int blen, llen;
- llen = ll2string(lbuf,32,l);
- blen = snprintf(bbuf,sizeof(bbuf),"$%u\r\n%s\r\n",llen,lbuf);
- if (fwrite(bbuf,blen,1,fp) == 0) return 0;
- return 1;
-}
-
-/* Delegate writing an object to writing a bulk string or bulk long long. */
-int fwriteBulkObject(FILE *fp, robj *obj) {
- /* Avoid using getDecodedObject to help copy-on-write (we are often
- * in a child process when this function is called). */
- if (obj->encoding == REDIS_ENCODING_INT) {
- return fwriteBulkLongLong(fp,(long)obj->ptr);
- } else if (obj->encoding == REDIS_ENCODING_RAW) {
- return fwriteBulkString(fp,obj->ptr,sdslen(obj->ptr));
- } else {
- redisPanic("Unknown string encoding");
- }
-}
-
-
projects / redis.git / blobdiff