git-p4: add read_pipe_text() internal function
The existing read_pipe() function returns an empty string on error, but also returns an empty string if the command returns an empty string. This leads to ugly constructions trying to detect error cases. Add read_pipe_text() which just returns None on error. Signed-off-by: Luke Diamand <luke@diamand.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Luke Diamand committed
Apr 15, 2017 at 11:36 UTC
78871bf46f18cd92e744a993c1d6422ff30d8bca
1 file changed
+28
-3
git-p4.py
+28
-3
@@ -160,17 +160,42 @@ def p4_write_pipe(c, stdin):
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real_cmd = p4_build_cmd(c)
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return write_pipe(real_cmd, stdin)
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-def read_pipe(c, ignore_error=False):
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+def read_pipe_full(c):
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+ """ Read output from command. Returns a tuple
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+ of the return status, stdout text and stderr
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+ text.
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+ """
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if verbose:
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sys.stderr.write('Reading pipe: %s\n' % str(c))
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expand = isinstance(c,basestring)
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p = subprocess.Popen(c, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=expand)
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(out, err) = p.communicate()
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- if p.returncode != 0 and not ignore_error:
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- die('Command failed: %s\nError: %s' % (str(c), err))
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+ return (p.returncode, out, err)
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+
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+def read_pipe(c, ignore_error=False):
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+ """ Read output from command. Returns the output text on
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+ success. On failure, terminates execution, unless
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+ ignore_error is True, when it returns an empty string.
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+ """
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+ (retcode, out, err) = read_pipe_full(c)
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+ if retcode != 0:
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+ if ignore_error:
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+ out = ""
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+ else:
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+ die('Command failed: %s\nError: %s' % (str(c), err))
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return out
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+def read_pipe_text(c):
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+ """ Read output from a command with trailing whitespace stripped.
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+ On error, returns None.
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+ """
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+ (retcode, out, err) = read_pipe_full(c)
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+ if retcode != 0:
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+ return None
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+ else:
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+ return out.rstrip()
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+
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def p4_read_pipe(c, ignore_error=False):
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real_cmd = p4_build_cmd(c)
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return read_pipe(real_cmd, ignore_error)