Show More
@@ -1,119 +1,120 b'' | |||
|
1 | 1 | """Common utilities for the various process_* implementations. |
|
2 | 2 | |
|
3 | 3 | This file is only meant to be imported by the platform-specific implementations |
|
4 | 4 | of subprocess utilities, and it contains tools that are common to all of them. |
|
5 | 5 | """ |
|
6 | 6 | |
|
7 | 7 | #----------------------------------------------------------------------------- |
|
8 | 8 | # Copyright (C) 2010 The IPython Development Team |
|
9 | 9 | # |
|
10 | 10 | # Distributed under the terms of the BSD License. The full license is in |
|
11 | 11 | # the file COPYING, distributed as part of this software. |
|
12 | 12 | #----------------------------------------------------------------------------- |
|
13 | 13 | |
|
14 | 14 | #----------------------------------------------------------------------------- |
|
15 | 15 | # Imports |
|
16 | 16 | #----------------------------------------------------------------------------- |
|
17 | 17 | import subprocess |
|
18 | 18 | import sys |
|
19 | 19 | |
|
20 | 20 | #----------------------------------------------------------------------------- |
|
21 | 21 | # Function definitions |
|
22 | 22 | #----------------------------------------------------------------------------- |
|
23 | 23 | |
|
24 | 24 | def read_no_interrupt(p): |
|
25 | 25 | """Read from a pipe ignoring EINTR errors. |
|
26 | 26 | |
|
27 | 27 | This is necessary because when reading from pipes with GUI event loops |
|
28 | 28 | running in the background, often interrupts are raised that stop the |
|
29 | 29 | command from completing.""" |
|
30 | 30 | import errno |
|
31 | 31 | |
|
32 | 32 | try: |
|
33 | 33 | return p.read() |
|
34 | 34 | except IOError, err: |
|
35 | 35 | if err.errno != errno.EINTR: |
|
36 | 36 | raise |
|
37 | 37 | |
|
38 | 38 | |
|
39 | 39 | def process_handler(cmd, callback, stderr=subprocess.PIPE): |
|
40 | 40 | """Open a command in a shell subprocess and execute a callback. |
|
41 | 41 | |
|
42 | 42 | This function provides common scaffolding for creating subprocess.Popen() |
|
43 | 43 | calls. It creates a Popen object and then calls the callback with it. |
|
44 | 44 | |
|
45 | 45 | Parameters |
|
46 | 46 | ---------- |
|
47 | 47 | cmd : str |
|
48 | 48 | A string to be executed with the underlying system shell (by calling |
|
49 | 49 | :func:`Popen` with ``shell=True``. |
|
50 | 50 | |
|
51 | 51 | callback : callable |
|
52 | 52 | A one-argument function that will be called with the Popen object. |
|
53 | 53 | |
|
54 | 54 | stderr : file descriptor number, optional |
|
55 | 55 | By default this is set to ``subprocess.PIPE``, but you can also pass the |
|
56 | 56 | value ``subprocess.STDOUT`` to force the subprocess' stderr to go into |
|
57 | 57 | the same file descriptor as its stdout. This is useful to read stdout |
|
58 | 58 | and stderr combined in the order they are generated. |
|
59 | 59 | |
|
60 | 60 | Returns |
|
61 | 61 | ------- |
|
62 | 62 | The return value of the provided callback is returned. |
|
63 | 63 | """ |
|
64 | 64 | sys.stdout.flush() |
|
65 | 65 | sys.stderr.flush() |
|
66 | close_fds = False if sys.platform=='win32' else True | |
|
66 | 67 | p = subprocess.Popen(cmd, shell=True, |
|
67 | 68 | stdin=subprocess.PIPE, |
|
68 | 69 | stdout=subprocess.PIPE, |
|
69 | 70 | stderr=stderr, |
|
70 |
close_fds= |
|
|
71 | close_fds=close_fds) | |
|
71 | 72 | |
|
72 | 73 | try: |
|
73 | 74 | out = callback(p) |
|
74 | 75 | except KeyboardInterrupt: |
|
75 | 76 | print('^C') |
|
76 | 77 | sys.stdout.flush() |
|
77 | 78 | sys.stderr.flush() |
|
78 | 79 | out = None |
|
79 | 80 | finally: |
|
80 | 81 | # Make really sure that we don't leave processes behind, in case the |
|
81 | 82 | # call above raises an exception |
|
82 | 83 | # We start by assuming the subprocess finished (to avoid NameErrors |
|
83 | 84 | # later depending on the path taken) |
|
84 | 85 | if p.returncode is None: |
|
85 | 86 | try: |
|
86 | 87 | p.terminate() |
|
87 | 88 | p.poll() |
|
88 | 89 | except OSError: |
|
89 | 90 | pass |
|
90 | 91 | # One last try on our way out |
|
91 | 92 | if p.returncode is None: |
|
92 | 93 | try: |
|
93 | 94 | p.kill() |
|
94 | 95 | except OSError: |
|
95 | 96 | pass |
|
96 | 97 | |
|
97 | 98 | return out |
|
98 | 99 | |
|
99 | 100 | |
|
100 | 101 | def getoutputerror(cmd): |
|
101 | 102 | """Return (standard output, standard error) of executing cmd in a shell. |
|
102 | 103 | |
|
103 | 104 | Accepts the same arguments as os.system(). |
|
104 | 105 | |
|
105 | 106 | Parameters |
|
106 | 107 | ---------- |
|
107 | 108 | cmd : str |
|
108 | 109 | A command to be executed in the system shell. |
|
109 | 110 | |
|
110 | 111 | Returns |
|
111 | 112 | ------- |
|
112 | 113 | stdout : str |
|
113 | 114 | stderr : str |
|
114 | 115 | """ |
|
115 | 116 | |
|
116 | 117 | out_err = process_handler(cmd, lambda p: p.communicate()) |
|
117 | 118 | if out_err is None: |
|
118 | 119 | out_err = '', '' |
|
119 | 120 | return out_err |
General Comments 0
You need to be logged in to leave comments.
Login now