closes #1173 - backporting python2.7 subprocess's check_output to be abl...

lib/matplotlib/backends/backend_pgf.py

@@ -19,6 +19,8 @@
 from matplotlib import font_manager
 from matplotlib.ft2font import FT2Font
 from matplotlib.cbook import is_string_like, is_writable_file_like
+from matplotlib.cbook import check_output
+
 
 ###############################################################################
 
@@ -150,14 +152,14 @@ def make_pdf_to_png_converter():
     tools_available = []
     # check for pdftocairo
     try:
-        subprocess.check_output(["pdftocairo", "-v"], stderr=subprocess.STDOUT)
+        check_output(["pdftocairo", "-v"], stderr=subprocess.STDOUT)
         tools_available.append("pdftocairo")
     except:
         pass
     # check for ghostscript
     try:
         gs = "gs" if sys.platform is not "win32" else "gswin32c"
-        subprocess.check_output([gs, "-v"], stderr=subprocess.STDOUT)
+        check_output([gs, "-v"], stderr=subprocess.STDOUT)
         tools_available.append("gs")
     except:
         pass
@@ -168,15 +170,15 @@ def cairo_convert(pdffile, pngfile, dpi):
             cmd = ["pdftocairo", "-singlefile", "-png",
                    "-r %d" % dpi, pdffile, os.path.splitext(pngfile)[0]]
             # for some reason this doesn't work without shell
-            subprocess.check_output(" ".join(cmd), shell=True, stderr=subprocess.STDOUT)
+            check_output(" ".join(cmd), shell=True, stderr=subprocess.STDOUT)
         return cairo_convert
     elif "gs" in tools_available:
         def gs_convert(pdffile, pngfile, dpi):
             cmd = [gs, '-dQUIET', '-dSAFER', '-dBATCH', '-dNOPAUSE', '-dNOPROMPT',
                    '-sDEVICE=png16m', '-dUseCIEColor', '-dTextAlphaBits=4',
                    '-dGraphicsAlphaBits=4', '-dDOINTERPOLATE', '-sOutputFile=%s' % pngfile,
                    '-r%d' % dpi, pdffile]
-            subprocess.check_output(cmd, stderr=subprocess.STDOUT)
+            check_output(cmd, stderr=subprocess.STDOUT)
         return gs_convert
     else:
         raise RuntimeError("No suitable pdf to png renderer found.")
@@ -719,7 +721,7 @@ def _print_pdf_to_fh(self, fh):
             texcommand = get_texcommand()
             cmdargs = [texcommand, "-interaction=nonstopmode", "-halt-on-error", "figure.tex"]
             try:
-                subprocess.check_output(cmdargs, stderr=subprocess.STDOUT)
+                check_output(cmdargs, stderr=subprocess.STDOUT)
             except subprocess.CalledProcessError as e:
                 raise RuntimeError("%s was not able to process your file.\n\nFull log:\n%s" % (texcommand, e.output))
 

lib/matplotlib/cbook.py

@@ -12,9 +12,10 @@
 from weakref import ref, WeakKeyDictionary
 import cPickle
 import os.path
-import random
 from functools import reduce
 
+import subprocess
+
 import matplotlib
 
 major, minor1, minor2, s, tmp = sys.version_info
@@ -1897,6 +1898,48 @@ def _putmask(a, mask, values):
         return np.copyto(a, values, where=mask)
 
 
+def _check_output(*popenargs, **kwargs):
+    r"""Run command with arguments and return its output as a byte
+    string.
+
+    If the exit code was non-zero it raises a CalledProcessError.  The
+    CalledProcessError object will have the return code in the
+    returncode
+    attribute and output in the output attribute.
+
+    The arguments are the same as for the Popen constructor.  Example:
+
+    >>> check_output(["ls", "-l", "/dev/null"])
+    'crw-rw-rw- 1 root root 1, 3 Oct 18  2007 /dev/null\n'
+
+    The stdout argument is not allowed as it is used internally.
+    To capture standard error in the result, use stderr=STDOUT.
+
+    >>> check_output(["/bin/sh", "-c",
+    ...               "ls -l non_existent_file ; exit 0"],
+    ...              stderr=STDOUT)
+    'ls: non_existent_file: No such file or directory\n'
+    """
+    if 'stdout' in kwargs:
+        raise ValueError('stdout argument not allowed, it will be overridden.')
+    process = subprocess.Popen(stdout=subprocess.PIPE, *popenargs, **kwargs)
+    output, unused_err = process.communicate()
+    retcode = process.poll()
+    if retcode:
+        cmd = kwargs.get("args")
+        if cmd is None:
+            cmd = popenargs[0]
+        raise subprocess.CalledProcessError(retcode, cmd, output=output)
+    return output
+
+
+# python2.7's subprocess provides a check_output method
+if hasattr(subprocess, 'check_output'):
+    check_output = subprocess.check_output
+else:
+    check_output = _check_output
+
+
 if __name__=='__main__':
     assert( allequal([1,1,1]) )
     assert(not  allequal([1,1,0]) )

lib/matplotlib/tests/test_backend_pgf.py

@@ -13,6 +13,7 @@
 
 baseline_dir, result_dir = _image_directories(lambda: 'dummy func')
 
+
 def check_for(texsystem):
     header = r"""
     \documentclass{minimal}
@@ -32,6 +33,7 @@ def check_for(texsystem):
 
     return latex.returncode == 0
 
+
 def switch_backend(backend):
 
     def switch_backend_decorator(func):
@@ -48,6 +50,7 @@ def backend_switcher(*args, **kwargs):
         return nose.tools.make_decorator(func)(backend_switcher)
     return switch_backend_decorator
 
+
 def compare_figure(fname):
     actual = os.path.join(result_dir, fname)
     plt.savefig(actual)
@@ -126,3 +129,7 @@ def test_rcupdate():
         mpl.rcParams.update(rc_set)
         create_figure()
         compare_figure('pgf_rcupdate%d.pdf' % (i+1))
+
+if __name__ == '__main__':
+    import nose
+    nose.runmodule(argv=['-s','--with-doctest'], exit=False)