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. */
| 83 | * Otherwise the operation fails, -1 is returned, and an unspecified amount of |
| 84 | * data could be read from the file descriptor. */ |
| 85 | ssize_t syncRead(int fd, char *ptr, ssize_t size, long long timeout) { |
| 86 | ssize_t nread, totread = 0; |
| 87 | long long start = mstime(); |
| 88 | long long remaining = timeout; |
| 89 | |
| 90 | if (size == 0) return 0; |
| 91 | while(1) { |
| 92 | long long wait = (remaining > SYNCIO__RESOLUTION) ? |
| 93 | remaining : SYNCIO__RESOLUTION; |
| 94 | long long elapsed; |
| 95 | |
| 96 | /* Optimistically try to read before checking if the file descriptor |
| 97 | * is actually readable. At worst we get EAGAIN. */ |
| 98 | nread = read(fd,ptr,size); |
| 99 | if (nread == 0) return -1; /* short read. */ |
| 100 | if (nread == -1) { |
| 101 | if (errno != EAGAIN) return -1; |
| 102 | } else { |
| 103 | ptr += nread; |
| 104 | size -= nread; |
| 105 | totread += nread; |
| 106 | } |
| 107 | if (size == 0) return totread; |
| 108 | |
| 109 | /* Wait */ |
| 110 | aeWait(fd,AE_READABLE,wait); |
| 111 | elapsed = mstime() - start; |
| 112 | if (elapsed >= timeout) { |
| 113 | errno = ETIMEDOUT; |
| 114 | return -1; |
| 115 | } |
| 116 | remaining = timeout - elapsed; |
| 117 | } |
| 118 | } |
| 119 | |
| 120 | /* Read a line making sure that every char will not require more than 'timeout' |
| 121 | * milliseconds to be read. |
no test coverage detected