From 1812f8cf3f47659a49712a3e2d633e82d1f09915 Mon Sep 17 00:00:00 2001 From: Peter Astrand Date: Sun, 7 Jan 2007 14:34:16 +0000 Subject: [PATCH] Avoid O(N**2) bottleneck in _communicate_(). Fixes #1598181. --- Lib/subprocess.py | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/Lib/subprocess.py b/Lib/subprocess.py index abd790dd92..ea1e0d1e12 100644 --- a/Lib/subprocess.py +++ b/Lib/subprocess.py @@ -1111,6 +1111,7 @@ class Popen(object): read_set.append(self.stderr) stderr = [] + input_offset = 0 while read_set or write_set: rlist, wlist, xlist = select.select(read_set, write_set, []) @@ -1118,9 +1119,9 @@ class Popen(object): # When select has indicated that the file is writable, # we can write up to PIPE_BUF bytes without risk # blocking. POSIX defines PIPE_BUF >= 512 - bytes_written = os.write(self.stdin.fileno(), input[:512]) - input = input[bytes_written:] - if not input: + bytes_written = os.write(self.stdin.fileno(), buffer(input, input_offset, 512)) + input_offset += bytes_written + if input_offset >= len(input): self.stdin.close() write_set.remove(self.stdin) -- 2.50.1