Support for patches in packages.

- packages can provide patch() directive to specify a patch file that
  should be applied to source code after expanding it and before
  building.

- patches can have a when spec, so they're only applied under certain
  conditions

- patches can be local files in the package's own directory, or they
  can be URLs which will be fetched from the internet.

8 files changed, 246 insertions, 13 deletions

diff --git a/lib/spack/spack/__init__.py b/lib/spack/spack/__init__.py
index 911309fed3..77aad98524 100644
--- a/lib/spack/spack/__init__.py
+++ b/lib/spack/spack/__init__.py
@@ -27,5 +27,5 @@ from util import *
 from error import *
 
 from package import Package
-from relations import depends_on, provides
+from relations import depends_on, provides, patch
 from multimethod import when
diff --git a/lib/spack/spack/cmd/patch.py b/lib/spack/spack/cmd/patch.py
new file mode 100644
index 0000000000..cc790df56e
--- /dev/null
+++ b/lib/spack/spack/cmd/patch.py
@@ -0,0 +1,51 @@
+##############################################################################
+# Copyright (c) 2013, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://scalability-llnl.github.io/spack
+# Please also see the LICENSE file for our notice and the LGPL.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License (as published by
+# the Free Software Foundation) version 2.1 dated February 1999.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
+# conditions of the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+import argparse
+
+import spack.cmd
+import spack.packages as packages
+
+
+description="Patch expanded archive sources in preparation for install"
+
+def setup_parser(subparser):
+    subparser.add_argument(
+        '-n', '--no-checksum', action='store_true', dest='no_checksum',
+        help="Do not check downloaded packages against checksum")
+    subparser.add_argument(
+        'packages', nargs=argparse.REMAINDER, help="specs of packages to stage")
+
+
+def patch(parser, args):
+    if not args.packages:
+        tty.die("patch requires at least one package argument")
+
+    if args.no_checksum:
+        spack.do_checksum = False
+
+    specs = spack.cmd.parse_specs(args.packages, concretize=True)
+    for spec in specs:
+        package = packages.get(spec)
+        package.do_patch()
diff --git a/lib/spack/spack/cmd/stage.py b/lib/spack/spack/cmd/stage.py
index 594d1f727d..2ce3d66bcb 100644
--- a/lib/spack/spack/cmd/stage.py
+++ b/lib/spack/spack/cmd/stage.py
@@ -33,7 +33,7 @@ description="Expand downloaded archive in preparation for install"
 def setup_parser(subparser):
     subparser.add_argument(
         '-n', '--no-checksum', action='store_true', dest='no_checksum',
-        help="Do not check packages against checksum")
+        help="Do not check downloaded packages against checksum")
     subparser.add_argument(
         'packages', nargs=argparse.REMAINDER, help="specs of packages to stage")
 
diff --git a/lib/spack/spack/package.py b/lib/spack/spack/package.py
index 7fe4d77b71..f733c5cbd2 100644
--- a/lib/spack/spack/package.py
+++ b/lib/spack/spack/package.py
@@ -55,6 +55,7 @@ from spack.stage import Stage
 from spack.util.lang import *
 from spack.util.web import get_pages
 from spack.util.environment import *
+from spack.util.filesystem import touch
 
 
 class Package(object):
@@ -267,10 +268,11 @@ class Package(object):
 
        p = Package()             # Done for you by spack
 
-       p.do_fetch()              # called by spack commands in spack/cmd.
-       p.do_stage()              # see spack.stage.Stage docs.
+       p.do_fetch()              # downloads tarball from a URL
+       p.do_stage()              # expands tarball in a temp directory
+       p.do_patch()              # applies patches to expanded source
        p.do_install()            # calls package's install() function
-       p.do_uninstall()
+       p.do_uninstall()          # removes install directory
 
     There are also some other commands that clean the build area:
 
@@ -304,6 +306,9 @@ class Package(object):
     """Specs of conflicting packages, keyed by name. """
     conflicted = {}
 
+    """Patches to apply to newly expanded source, if any."""
+    patches = {}
+
     #
     # These are default values for instance variables.
     #
@@ -569,6 +574,9 @@ class Package(object):
         """Creates a stage directory and downloads the taball for this package.
            Working directory will be set to the stage directory.
         """
+        if not self.spec.concrete:
+            raise ValueError("Can only fetch concrete packages.")
+
         if spack.do_checksum and not self.version in self.versions:
             tty.die("Cannot fetch %s@%s safely; there is no checksum on file for this "
                     "version." % (self.name, self.version),
@@ -590,6 +598,9 @@ class Package(object):
     def do_stage(self):
         """Unpacks the fetched tarball, then changes into the expanded tarball
            directory."""
+        if not self.spec.concrete:
+            raise ValueError("Can only stage concrete packages.")
+
         self.do_fetch()
 
         archive_dir = self.stage.expanded_archive_path
@@ -601,6 +612,52 @@ class Package(object):
         self.stage.chdir_to_archive()
 
 
+    def do_patch(self):
+        """Calls do_stage(), then applied patches to the expanded tarball if they
+           haven't been applied already."""
+        if not self.spec.concrete:
+            raise ValueError("Can only patch concrete packages.")
+
+        self.do_stage()
+
+        # Construct paths to special files in the archive dir used to
+        # keep track of whether patches were successfully applied.
+        archive_dir = self.stage.expanded_archive_path
+        good_file = new_path(archive_dir, '.spack_patched')
+        bad_file  = new_path(archive_dir, '.spack_patch_failed')
+
+        # If we encounter an archive that failed to patch, restage it
+        # so that we can apply all the patches again.
+        if os.path.isfile(bad_file):
+            tty.msg("Patching failed last time.  Restaging.")
+            self.stage.restage()
+
+        self.stage.chdir_to_archive()
+
+        # If this file exists, then we already applied all the patches.
+        if os.path.isfile(good_file):
+            tty.msg("Already patched %s" % self.name)
+            return
+
+        # Apply all the patches for specs that match this on
+        for spec, patch_list in self.patches.items():
+            if self.spec.satisfies(spec):
+                for patch in patch_list:
+                    tty.msg('Applying patch %s' % patch.path_or_url)
+                    try:
+                        patch.apply(self.stage)
+                    except:
+                        # Touch bad file if anything goes wrong.
+                        touch(bad_file)
+                        raise
+
+        # patch succeeded.  Get rid of failed file & touch good file so we
+        # don't try to patch again again next time.
+        if os.path.isfile(bad_file):
+            os.remove(bad_file)
+        touch(good_file)
+
+
     def do_install(self):
         """This class should call this version of the install method.
            Package implementations should override install().
@@ -616,7 +673,7 @@ class Package(object):
         if not self.ignore_dependencies:
             self.do_install_dependencies()
 
-        self.do_stage()
+        self.do_patch()
         self.setup_install_environment()
 
         # Add convenience commands to the package's module scope to
diff --git a/lib/spack/spack/packages/__init__.py b/lib/spack/spack/packages/__init__.py
index d9791ed1bc..488aea2423 100644
--- a/lib/spack/spack/packages/__init__.py
+++ b/lib/spack/spack/packages/__init__.py
@@ -209,6 +209,12 @@ def validate_package_name(pkg_name):
         raise InvalidPackageNameError(pkg_name)
 
 
+def dirname_for_package_name(pkg_name):
+    """Get the directory name for a particular package would use, even if it's a
+       foo.py package and not a directory with a foo/__init__.py file."""
+    return new_path(spack.packages_path, pkg_name)
+
+
 def filename_for_package_name(pkg_name):
     """Get the filename for the module we should load for a particular package.
        The package can be either in a standalone .py file, or it can be in
@@ -227,8 +233,7 @@ def filename_for_package_name(pkg_name):
        of the standalone .py file.
     """
     validate_package_name(pkg_name)
-
-    pkg_dir   = new_path(spack.packages_path, pkg_name)
+    pkg_dir = dirname_for_package_name(pkg_name)
 
     if os.path.isdir(pkg_dir):
         init_file = new_path(pkg_dir, '__init__.py')
diff --git a/lib/spack/spack/patch.py b/lib/spack/spack/patch.py
new file mode 100644
index 0000000000..82a3a92449
--- /dev/null
+++ b/lib/spack/spack/patch.py
@@ -0,0 +1,94 @@
+##############################################################################
+# Copyright (c) 2013, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://scalability-llnl.github.io/spack
+# Please also see the LICENSE file for our notice and the LGPL.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License (as published by
+# the Free Software Foundation) version 2.1 dated February 1999.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
+# conditions of the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+import os
+
+import spack
+import spack.stage
+import spack.error
+import spack.packages as packages
+import spack.tty as tty
+
+from spack.util.executable import which
+from spack.util.filesystem import new_path
+
+# Patch tool for patching archives.
+_patch = which("patch", required=True)
+
+
+class Patch(object):
+    """This class describes a patch to be applied to some expanded
+       source code."""
+
+    def __init__(self, pkg_name, path_or_url, level):
+        self.pkg_name = pkg_name
+        self.path_or_url = path_or_url
+        self.path = None
+        self.url = None
+        self.level = level
+
+        if not isinstance(self.level, int) or not self.level >= 0:
+            raise ValueError("Patch level needs to be a non-negative integer.")
+
+        if '://' in path_or_url:
+            self.url = path_or_url
+        else:
+            pkg_dir = packages.dirname_for_package_name(pkg_name)
+            self.path = new_path(pkg_dir, path_or_url)
+            if not os.path.isfile(self.path):
+                raise NoSuchPatchFileError(pkg_name, self.path)
+
+
+    def apply(self, stage):
+        """Fetch this patch, if necessary, and apply it to the source
+           code in the supplied stage.
+        """
+        stage.chdir_to_archive()
+
+        patch_stage = None
+        try:
+            if self.url:
+                # use an anonymous stage to fetch the patch if it is a URL
+                patch_stage = spack.stage.Stage(self.url)
+                patch_stage.fetch()
+                patch_file = patch_stage.archive_file
+            else:
+                patch_file = self.path
+
+            # Use -N to allow the same patches to be applied multiple times.
+            _patch('-s', '-p', str(self.level), '-i', patch_file)
+
+        finally:
+            if patch_stage:
+                patch_stage.destroy()
+
+
+
+class NoSuchPatchFileError(spack.error.SpackError):
+    """Raised when user specifies a patch file that doesn't exist."""
+    def __init__(self, package, path):
+        super(NoSuchPatchFileError, self).__init__(
+            "No such patch file for package %s: %s" % (package, path))
+        self.package = package
+        self.path = path
diff --git a/lib/spack/spack/relations.py b/lib/spack/spack/relations.py
index 1c24db5fa6..28c9bf0363 100644
--- a/lib/spack/spack/relations.py
+++ b/lib/spack/spack/relations.py
@@ -75,6 +75,8 @@ import importlib
 import spack
 import spack.spec
 import spack.error
+
+from spack.patch import Patch
 from spack.spec import Spec, parse_anonymous_spec
 from spack.packages import packages_module
 from spack.util.lang import *
@@ -110,16 +112,35 @@ def provides(*specs, **kwargs):
             provided[provided_spec] = provider_spec
 
 
-"""Packages can declare conflicts with other packages.
-   This can be as specific as you like: use regular spec syntax.
-"""
+def patch(url_or_filename, **kwargs):
+    """Packages can declare patches to apply to source.  You can
+       optionally provide a when spec to indicate that a particular
+       patch should only be applied when the package's spec meets
+       certain conditions (e.g. a particular version).
+    """
+    pkg = get_calling_package_name()
+    level = kwargs.get('level', 1)
+    when_spec = parse_anonymous_spec(kwargs.get('when', pkg), pkg)
+
+    patches = caller_locals().setdefault('patches', {})
+    if when_spec not in patches:
+        patches[when_spec] = [Patch(pkg, url_or_filename, level)]
+    else:
+        # if this spec is identical to some other, then append this
+        # patch to the existing list.
+        patches[when_spec].append(Patch(pkg, url_or_filename, level))
+
+
 def conflicts(*specs):
+    """Packages can declare conflicts with other packages.
+       This can be as specific as you like: use regular spec syntax.
+
+       NOT YET IMPLEMENTED.
+    """
     # TODO: implement conflicts
     pass
 
 
-
-
 class RelationError(spack.error.SpackError):
     """This is raised when something is wrong with a package relation."""
     def __init__(self, relation, message):
diff --git a/lib/spack/spack/util/filesystem.py b/lib/spack/spack/util/filesystem.py
index d3c7b16457..c84a9fd608 100644
--- a/lib/spack/spack/util/filesystem.py
+++ b/lib/spack/spack/util/filesystem.py
@@ -57,6 +57,11 @@ def working_dir(dirname):
     os.chdir(orig_dir)
 
 
+def touch(path):
+    with closing(open(path, 'a')) as file:
+        os.utime(path, None)
+
+
 def mkdirp(*paths):
     for path in paths:
         if not os.path.exists(path):