overlay/pkgdir/symlink/distroot: HardlinkDistroot

added HardlinkDistroot, a distroot class that manages package files
in a flat hardlink structure (one dir for all links).
This will be used as replacement for the __tmp__ dir in pkgdir_ebuildmanifest.

1 files changed, 143 insertions, 52 deletions

diff --git a/roverlay/overlay/pkgdir/symlink/distroot.py b/roverlay/overlay/pkgdir/symlink/distroot.py
index 7345d98..269be94 100644
--- a/roverlay/overlay/pkgdir/symlink/distroot.py
+++ b/roverlay/overlay/pkgdir/symlink/distroot.py
@@ -4,7 +4,10 @@
 # Distributed under the terms of the GNU General Public License;
 # either version 2 of the License, or (at your option) any later version.
 
-__all__ = [ 'SymlinkDistroot', 'ThreadsafeSymlinkDistroot' ]
+__all__ = [
+	'SymlinkDistroot', 'ThreadsafeSymlinkDistroot', 'HardlinkDistroot',
+	'LinkDistrootBase',
+]
 
 import os
 import atexit
@@ -17,26 +20,14 @@ import roverlay.config
 
 import roverlay.overlay.pkgdir.symlink.distdir
 
-class _SymlinkDistrootBase ( object ):
+class LinkDistrootBase ( object ):
+	"""Base class for sym-/hardlink distroots."""
 
 	_instance_lock = threading.Lock()
-	__instance     = None
 
 	@classmethod
 	def get_configured ( cls ):
-		"""Returns the static SymlinkDistroot instance."""
-		if cls.__instance is None:
-			with cls._instance_lock:
-				if cls.__instance is None:
-					cls.__instance = cls (
-						root = roverlay.config.get (
-							'OVERLAY.SYMLINK_DISTROOT.root', ""
-						),
-						is_tmpdir = roverlay.config.get_or_fail (
-							'OVERLAY.SYMLINK_DISTROOT.tmp'
-						),
-					)
-		return cls.__instance
+		raise NotImplementedError()
 	# --- end of get_configured (...) ---
 
 	def __repr__ ( self ):
@@ -50,7 +41,7 @@ class _SymlinkDistrootBase ( object ):
 	# --- end of __str__ (...) ---
 
 	def __init__ ( self, root, is_tmpdir ):
-		"""Initializes a _SymlinkDistrootBase instance.
+		"""Initializes a LinkDistrootBase instance.
 
 		arguments:
 		* root      -- root directory where per-package SymlinkDistdirs will
@@ -65,7 +56,7 @@ class _SymlinkDistrootBase ( object ):
 
 		Raises: ConfigError if root is not set and is_tmpdir evaluates to False.
 		"""
-		super ( _SymlinkDistrootBase, self ).__init__()
+		super ( LinkDistrootBase, self ).__init__()
 
 		self._root      = root
 		self._is_tmpdir = bool ( is_tmpdir )
@@ -116,10 +107,135 @@ class _SymlinkDistrootBase ( object ):
 	# --- end of get (...) ---
 
 	def _prepare ( self ):
+		"""Prepares the distroot.
+		Called for both temporary and persistent distroots.
+		"""
+		pass
+	# --- end of _prepare (...) ---
+
+	def get ( self, package_name ):
+		"""Returns a distdir object for the given package.
+
+		arguments:
+		* package_name
+
+		Has to be implemented by derived classes.
+
+		Note: the returned object can also be this object ("self")
+		"""
+		raise NotImplementedError()
+	# --- end of get (...) ---
+
+# --- end of LinkDistrootBase ---
+
+class HardlinkDistroot ( LinkDistrootBase ):
+	"""A directory that combines distroot and distdir functionality and
+	manages distfiles using hardlinks.
+
+	=> flat structure (single dir that contains links to all package files)
+	"""
+
+	__instance = None
+
+	@classmethod
+	def get_configured ( cls ):
+		"""Returns the static SymlinkDistroot instance.
+
+		Relevant config keys:
+		* OVERLAY.HARDLINK_DISTROOT.root
+		"""
+		if cls.__instance is None:
+			with cls._instance_lock:
+				if cls.__instance is None:
+					cls.__instance = cls (
+						root = roverlay.config.get (
+							'OVERLAY.HARDLINK_DISTROOT.root', ""
+						),
+					)
+		return cls.__instance
+	# --- end of get_configured (...) ---
+
+	def __init__ ( self, root ):
+		# is_tmpdir does not seem to be useful for this class
+		super ( HardlinkDistroot ).__init__ (
+			root      = root,
+			is_tmpdir = False
+		)
+	# --- end of __init__ (...) ---
+
+	def get ( self, package_name ):
+		# compat function
+		return self
+	# --- end of get (...) ---
+
+	def add ( self, fpath, fname=None ):
+		"""Adds a hardlink to a file to this dir.
+
+		Replaces existing files/hardlinks.
+
+		arguments:
+		* fpath -- path to the file for which a symlink will be created
+		* fname -- name of the symlink, defaults to os.path.basename ( fpath )
+		"""
+		hardlink = self.root + os.sep + ( fname or os.path.basename ( fpath ) )
+
+		# assume that the hardlink already exists
+		try:
+			os.unlink ( hardlink )
+		except OSError as oserr:
+			if oserr.errno == 2:
+				pass
+			else:
+				raise
+
+		os.link ( fpath, hardlink )
+	# --- end of add (...) ---
+
+# --- end of HardlinkDistroot ---
+
+class SymlinkDistroot ( LinkDistrootBase ):
+	"""A symlink distroot that uses a dict to remember
+	per-package SymlinkDistdirs.
+	"""
+
+	__instance = None
+
+	@classmethod
+	def get_configured ( cls ):
+		"""Returns the static SymlinkDistroot instance.
+
+		Relevant config keys:
+		* OVERLAY.SYMLINK_DISTROOT.root
+		* OVERLAY.SYMLINK_DISTROOT.tmp
+		"""
+		if cls.__instance is None:
+			with cls._instance_lock:
+				if cls.__instance is None:
+					cls.__instance = cls (
+						root = roverlay.config.get (
+							'OVERLAY.SYMLINK_DISTROOT.root', ""
+						),
+						is_tmpdir = roverlay.config.get_or_fail (
+							'OVERLAY.SYMLINK_DISTROOT.tmp'
+						),
+					)
+		return cls.__instance
+	# --- end of get_configured (...) ---
+
+	# _not_ threadsafe, but get() is expected to be called
+	#  within a (per-package_name) threadsafe context
+
+	def __init__ ( self, *args, **kwargs ):
+		"""see LinkDistrootBase.__init__()"""
+		super ( SymlinkDistroot, self ).__init__ ( *args, **kwargs )
+		self._subdirs = dict()
+	# --- end of __init__ (...) ---
+
+	def _prepare ( self ):
 		"""Prepares the SymlinkDistroot. Called for both temporary and
 		persistent distroots.
 
-		The default actions is to remove broken symlinks.
+		The default action is to remove broken symlinks.
 		"""
 		if not self._is_tmpdir:
 			self.remove_broken_symlinks ( unsafe_assumptions=True )
@@ -129,11 +245,13 @@ class _SymlinkDistrootBase ( object ):
 		"""Returns a SymlinkDistdir for the given package.
 
 		arguments:
-		* package_name
-
-		Has to be implemented by derived classes.
+		* package_name --
 		"""
-		raise NotImplementedError()
+		try:
+			return self._subdirs [package_name]
+		except KeyError:
+			self._subdirs [package_name] = self._get ( package_name )
+			return self._subdirs [package_name]
 	# --- end of get (...) ---
 
 	def remove_broken_symlinks ( self, unsafe_assumptions=False ):
@@ -180,35 +298,6 @@ class _SymlinkDistrootBase ( object ):
 
 	# --- end of remove_broken_symlinks (...) ---
 
-# --- end of _SymlinkDistrootBase ---
-
-class SymlinkDistroot ( _SymlinkDistrootBase ):
-	"""A symlink distroot that uses a dict to remember
-	per-package SymlinkDistdirs.
-	"""
-
-	# _not_ threadsafe, but get() is expected to be called
-	#  within a (per-package_name) threadsafe context
-
-	def __init__ ( self, *args, **kwargs ):
-		"""see _SymlinkDistrootBase.__init__()"""
-		super ( SymlinkDistroot, self ).__init__ ( *args, **kwargs )
-		self._subdirs = dict()
-	# --- end of __init__ (...) ---
-
-	def get ( self, package_name ):
-		"""Returns a SymlinkDistdir for the given package.
-
-		arguments:
-		* package_name --
-		"""
-		try:
-			return self._subdirs [package_name]
-		except KeyError:
-			self._subdirs [package_name] = self._get ( package_name )
-			return self._subdirs [package_name]
-	# --- end of get (...) ---
-
 # --- end of SymlinkDistroot ---
 
 class ThreadsafeSymlinkDistroot ( SymlinkDistroot ):
@@ -216,6 +305,8 @@ class ThreadsafeSymlinkDistroot ( SymlinkDistroot ):
 
 	# will be removed if SymlinkDistroot is sufficient.
 
+	__instance = None
+
 	def __init__ ( self, *args, **kwargs ):
 		super ( ThreadsafeSymlinkDistroot, self ).__init__ ( *args, **kwargs )
 		self._lock = threading.Lock()