[Piglit] [PATCH v4 5/6] framework: add support for lzma via shell calls

[Dylan Baker]

This requires that there is an xz binary installed, and accessible,
obviously.

v4: - add this patch

Signed-off-by: Dylan Baker <dylanx.c.baker at intel.com>
---
 framework/backends/compression.py           | 82 ++++++++++++++++++++++++++++-
 framework/tests/compressed_backend_tests.py | 17 ++++++
 2 files changed, 98 insertions(+), 1 deletion(-)

diff --git a/framework/backends/compression.py b/framework/backends/compression.py
index 153dc94..ef97c95 100644
--- a/framework/backends/compression.py
+++ b/framework/backends/compression.py
@@ -43,15 +43,17 @@ they're passing unicode and not bytes.
 
 from __future__ import print_function, absolute_import, division
 import bz2
+import errno
 import functools
 import gzip
 import os
+import subprocess
 
 from framework import exceptions
 from framework.core import PIGLIT_CONFIG
 
-# TODO: in python3 the bz2 module has an open function
 
+# TODO: in python3 the bz2 module has an open function
 COMPRESSION_SUFFIXES = ['.gz', '.bz2']
 
 DEFAULT = 'bz2'
@@ -68,6 +70,84 @@ DECOMPRESSORS = {
     'none': functools.partial(open, mode='r'),
 }
 
+# TODO: in python3 there is builtin xz support, and doesn't need this madness
+# If there is an xz binary then try calling out to that
+try:
+    with open(os.devnull, 'w') as d:
+        subprocess.check_call(['xz'], stderr=d)
+except subprocess.CalledProcessError as e:
+    if e.returncode == 1:
+        import contextlib
+        try:
+            import cStringIO as StringIO
+        except ImportError:
+            import StringIO
+
+        @contextlib.contextmanager
+        def _compress_xz(filename):
+            """Emulates an open function in write mode for xz.
+
+            Python 2.x doesn't support xz, but it's dang useful. This function calls
+            out to the shell and tries to use xz from the environment to get xz
+            compression.
+
+            This obviously won't work without a working xz binary.
+
+            This function tries to emulate the default values of the lzma module in
+            python3 as much as possible
+
+            """
+            if filename.endswith('.xz'):
+                filename = filename[:-2]
+
+            with open(filename, 'w') as f:
+                yield f
+
+            try:
+                subprocess.check_call(['xz', '--compress', '-9', filename])
+            except OSError as e:
+                if e.errno == errno.ENOENT:
+                    raise exceptions.PiglitFatalError('No xz binary available')
+                raise
+
+        @contextlib.contextmanager
+        def _decompress_xz(filename):
+            """Eumlates an option function in read mode for xz.
+
+            See the comment in _compress_xz for more information.
+
+            This module tries to emulate the lzma module as much as possible
+
+            """
+            if not filename.endswith('.xz'):
+                filename = '{}.xz'.format(filename)
+
+            print('decompress: ' + filename)
+
+            try:
+                string = subprocess.check_output(
+                    ['xz', '--decompress', '--stdout', filename])
+            except OSError as e:
+                if e.errno == errno.ENOENT:
+                    raise exceptions.PiglitFatalError('No xz binary available')
+                raise
+
+            # We need a file-like object, so the contents must be placed in a StringIO
+            # object.
+            io = StringIO.StringIO()
+            io.write(string)
+            io.seek(0)
+
+            yield io
+
+            io.close()
+
+        COMPRESSORS['xz'] = _compress_xz
+        DECOMPRESSORS['xz'] = _decompress_xz
+        COMPRESSION_SUFFIXES += ['.xz']
+except OSError:
+    pass
+
 
 def _set_mode():
     """Set the compression mode.
diff --git a/framework/tests/compressed_backend_tests.py b/framework/tests/compressed_backend_tests.py
index 7af633d..2353c7b 100644
--- a/framework/tests/compressed_backend_tests.py
+++ b/framework/tests/compressed_backend_tests.py
@@ -218,3 +218,20 @@ def test_decompress_bz2():
 def test_bz2_output():
     """framework.backends: when using bz2 compression a bz2 file is created"""
     nt.eq_(_test_extension(), '.bz2')
+
+
+ at utils.no_error
+def test_compress_xz():
+    """framework.backends.compression: can compress to 'xz'"""
+    _test_compressor('xz')
+
+
+def test_decompress_xz():
+    """framework.backends.compression: can decompress from 'xz'"""
+    _test_decompressor('xz')
+
+
+ at _set_compression_mode('xz')
+def test_xz_output():
+    """framework.backends: when using xz compression a xz file is created"""
+    nt.eq_(_test_extension(), '.xz')
-- 
2.4.5