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Checking whether a read will block and then learning stdin
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| ''' | |
| Basic functions for clearing stdin by checking whether a | |
| read will block. | |
| ''' | |
| import select | |
| import sys | |
| def has_unread_input(stream=sys.stdin, timeout=0): | |
| ''' | |
| Where stream is a readable file-descriptor, returns | |
| True if the given stream has input waiting to be read. | |
| Otherwise returns False. | |
| The default timeout of zero indicates that the given | |
| stream should be polled for input and the function | |
| returns immediately. Increasing the timeout will cause | |
| the function to wait that many seconds for the poll to | |
| succeed. Setting timeout to None will cause the function | |
| to block until it can return True. | |
| ''' | |
| return stream in select.select([stream], [], [], timeout)[0] | |
| def discard_input(stream=sys.stdin): | |
| ''' | |
| Where stream is a readable file-descriptor, reads | |
| all available data and returns any bytes read. If no | |
| data is available, then an empty set of bytes is | |
| returned. | |
| ''' | |
| data = bytearray() | |
| while has_unread_input(stream): | |
| data.extend(stream.readline()) | |
| return bytes(data) | |
| def refreshed_input(prompt=''): | |
| ''' | |
| Clears stdin before writing the given prompt and | |
| waiting for input from stdin. Returns the given | |
| input as a string with the trailing-newline removed. | |
| ''' | |
| discard_input(sys.stdin) | |
| try: | |
| return raw_input(prompt) | |
| except NameError: | |
| return input(prompt) |
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