[PATCH 2/3] git-p4: add read_pipe_text() internal function

From

Luke Diamand <luke@diamand.org>

Date

Apr 15, 2017, 10:36 UTC

Message-ID

<20170415103609.6002-3-luke@diamand.org>

In-Reply-To

<20170415103609.6002-1-luke@diamand.org>

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>
---
 git-p4.py | 31 ++++++++++++++++++++++++++++---
 1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/git-p4.py b/git-p4.py
index eab319d76..584b81775 100755
--- a/git-p4.py
+++ b/git-p4.py
@@ -160,17 +160,42 @@ def p4_write_pipe(c, stdin):
     real_cmd = p4_build_cmd(c)
     return write_pipe(real_cmd, stdin)
 
-def read_pipe(c, ignore_error=False):
+def read_pipe_full(c):
+    """ Read output from  command. Returns a tuple
+        of the return status, stdout text and stderr
+        text.
+    """
     if verbose:
         sys.stderr.write('Reading pipe: %s\n' % str(c))
 
     expand = isinstance(c,basestring)
     p = subprocess.Popen(c, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=expand)
     (out, err) = p.communicate()
-    if p.returncode != 0 and not ignore_error:
-        die('Command failed: %s\nError: %s' % (str(c), err))
+    return (p.returncode, out, err)
+
+def read_pipe(c, ignore_error=False):
+    """ Read output from  command. Returns the output text on
+        success. On failure, terminates execution, unless
+        ignore_error is True, when it returns an empty string.
+    """
+    (retcode, out, err) = read_pipe_full(c)
+    if retcode != 0:
+        if ignore_error:
+            out = ""
+        else:
+            die('Command failed: %s\nError: %s' % (str(c), err))
     return out
 
+def read_pipe_text(c):
+    """ Read output from a command with trailing whitespace stripped.
+        On error, returns None.
+    """
+    (retcode, out, err) = read_pipe_full(c)
+    if retcode != 0:
+        return None
+    else:
+        return out.rstrip()
+
 def p4_read_pipe(c, ignore_error=False):
     real_cmd = p4_build_cmd(c)
     return read_pipe(real_cmd, ignore_error)

-- 
2.12.2.719.gcbd162c