Ichthyostega
d24e025de2
Many years ago, I integrated the IconSvgRenderer (written by Joel Holdsworth) directly into the SCons build by means of a custom builder with an ''emitter function''. The build as such works fine and automatically determines which icons can be generated from a given SVG source. However, those SVG icons tend to be rebuilt very frequently, even while none of the SVG sources has changed. Basically this was more of an annoyance, since we have now about 15 icons and the rendering is really fast ... it is just ugly, especially on incremental builds (and it could become a problem once we have a massive amount of graphics to process. So I took the opportunity to take close look now, since I am doing uninspiring clean-up work since several weeks now. But that problem turned out to be quite insidious and hard to spot. First, AI set me off into a completely wrong angle, since it is ''not'' caused by a missing string representation of the custom Action class. However, from there I went to watching the target checks with the debugger, and this eventually got me to realise, that SCons mistakenly detects a change in the Executor / the Action class. The root cause is, that we invoke Python code from an external Module, IconSvgRenderer.py, and this is »materialised« by SCons automatically into a string representation, which includes memory addresses of functions in that module. And that yields a signature, that is, quite obviously, not stable, even while you end up sometimes with loading the code to the same memory location. As a solution / workaround, we now subclass the standard implementation from SCons and override the signature function; instead of fingerprinting the binary code, we just compute a MD5 over the python source file, which can be easily achieved with the help of the File-Node from SCons. Essential resources: https://scons.org/doc/4.8.0/HTML/scons-user.html#chap-builders-writing ...and the Reference / Manpage of SCons https://scons.org/doc/4.8.0/HTML/scons-man.html#action_objects SCons/Action.py SCons/Node/__init__.py
473 lines
20 KiB
Python
473 lines
20 KiB
Python
# coding: utf-8
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##
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## LumieraEnvironment.py - custom SCons Environment
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##
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# Copyright (C)
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# 2008-2025 Hermann Vosseler <Ichthyostega@web.de>
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#
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# **Lumiera** is free software; you can redistribute it and/or modify it
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# under the terms of the GNU General Public License as published by the
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# Free Software Foundation; either version 2 of the License, or (at your
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# option) any later version. See the file COPYING for further details.
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#####################################################################
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from os import path
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import SCons.SConf
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from SCons.Action import Action, FunctionAction
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from SCons.Script import File as SConsFile
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from SCons.Environment import Environment
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from Buildhelper import *
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class LumieraEnvironment(Environment):
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""" Custom SCons build environment for Lumiera
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This allows us to carry structured config data without
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using global vars. Idea inspired by Ardour.
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"""
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def __init__(self, buildSetup, buildVars, **kw):
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Environment.__init__ (self, toolpath = [buildSetup.TOOLDIR ]
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, variables = buildVars # ◁───── reads settings from the commandline (see Options.py)
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, **kw)
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#
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self['TARGDIR'] = buildSetup.TARGDIR
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self['VERSION'] = buildSetup.VERSION
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self['DESTDIR'] = '$INSTALLDIR/$PREFIX'
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self['SHARE' ] = '$DESTDIR/share'
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self._anchor_relative('INSTALLDIR')
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self._anchor_relative('TARGDIR')
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#
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self.path = Record (extract_localPathDefs(buildSetup)) # ◁───── e.g. buildExe -> env.path.buildExe
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self.libInfo = {}
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self.Tool("BuilderDoxygen")
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self.Tool("ToolDistCC")
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self.Tool("ToolCCache")
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register_LumieraIconBuilder(self)
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register_LumieraResourceBuilders(self)
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register_LumieraCustomBuilders(self)
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def _anchor_relative(self, key):
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""" ensure that a relative path spec becomes anchored at build-root
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@note: a special convention within scons: '#' implies directory of SConstruct
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"""
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spec = self[key].strip()
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if not (spec.startswith('/') or spec.startswith('#')):
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spec = '#'+spec
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self[key] = spec
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def Configure (self, *args, **kw):
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kw['env'] = self
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return LumieraConfigContext(*args, **kw)
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def mergeConf (self,other):
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""" extract the library/compiler flags from other Environment.
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Optionally accepts a list or just sting(s) representing keys
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in our own libInfo Dictionary
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"""
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if isinstance(other, list):
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for elm in other:
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self.mergeConf(elm)
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elif isinstance(other, str):
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if other in self.libInfo:
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self.mergeConf(self.libInfo[other])
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else:
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self.Append (LIBS = other.get('LIBS',[]))
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self.Append (LIBPATH = other.get('LIBPATH', []))
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self.Append (CPPPATH = other.get('CPPPATH', []))
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self.Append (LINKFLAGS = other.get('LINKFLAGS', []))
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return self
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def addLibInfo (self, libID, minVersion=0, alias=None):
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""" use pkg-config to create an Environment describing the lib.
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Don't add this defs to the current Environment, rather store
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them in the libInfo Dictionary.
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"""
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minVersion = str(minVersion)
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if 0 != os.system('pkg-config --print-errors --exists "%s >= %s"' % (libID,minVersion)):
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print("Problems configuring the Library %s (>= %s)" % (libID,minVersion))
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return False
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self.libInfo[libID] = libInfo = Environment()
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libInfo["ENV"]["PKG_CONFIG_PATH"] = os.environ.get("PKG_CONFIG_PATH")
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libInfo.ParseConfig ('pkg-config --cflags --libs '+ libID )
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if alias:
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self.libInfo[alias] = libInfo
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return libInfo
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# extending the 'Configure' functionality of SCons,
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# especially for library dependency checking
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ConfigBase = SCons.SConf.SConfBase
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class LumieraConfigContext(ConfigBase):
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""" Extends the SCons Configure context with some convenience methods
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"""
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def __init__(self, *args,**kw):
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ConfigBase.__init__(self,*args,**kw)
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def CheckPkgConfig (self, libID, minVersion=0, alias=None):
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print("Checking for library configuration: %s " % libID)
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# self.Message(self,"Checking for library configuration: %s " % libID)
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return self.env.addLibInfo (libID, minVersion, alias)
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###############################################################################
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####### Lumiera custom tools and builders #####################################
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def register_LumieraIconBuilder(env):
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""" Registers a custom Builder for generating and installing Icons from SVG.
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Additionally you need to build the tool (rsvg-convert.c)
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used to generate png from the svg source using librsvg.
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"""
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import IconSvgRenderer as renderer # load Joel's python script for invoking the rsvg-convert (SVG render)
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renderer.rsvgPath = env.subst("$TARGDIR/rsvg-convert").removeprefix('#')
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# # the prefix '#' is a SCons specific convention,
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# # which the external tool can not handle
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#
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# MD5 signature for this specific python source code...
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thisCodeSignature = SConsFile(__file__).get_csig() + SConsFile(renderer.__file__).get_csig()
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thisCodeSignature = bytearray(thisCodeSignature, 'utf-8')
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class IconRenderAction(FunctionAction):
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""" SCons Action subclass to provide a controlled cache signature.
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@note: usually it would be sufficient to pass just a callable to the Builder,
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however, our implementation calls into an external Python module and thus
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the default signature from SCons would not be stable, since it relies
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on a code representation including memory addresses. Without this,
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the icons would be frequently rebuilt unnecessarily.
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"""
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def __init__(self):
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FunctionAction.__init__(self, IconRenderAction.invokeRenderer
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, {'cmdstr' : "rendering Icon: $SOURCE --> $TARGETS"}
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)
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def get_contents(self, target, source, env):
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""" a stable signature based on the source code """
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return thisCodeSignature
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@staticmethod
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def invokeRenderer(target, source, env):
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""" render the SVG icon with libRSVG """
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source = str(source[0])
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targetdir = env.subst(env.path.buildIcon).removeprefix('#')
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renderer.main([source,targetdir])
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return 0
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def createIconTargets(target,source,env):
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""" parse the SVG to get the target file names """
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source = str(source[0])
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targetdir = env.path.buildIcon
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targetfiles = renderer.getTargetNames(source) # parse SVG
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# additionally create an installation task for each Icon to be generated
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installLocation = env.path.installIcon
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generateTargets = []
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for icon in targetfiles:
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icon = targetdir+icon
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subdir = getDirname(str(icon))
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env.Install (installLocation+subdir, icon)
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generateTargets.append(icon)
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return (generateTargets, source)
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buildIcon = env.Builder( action = IconRenderAction()
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, single_source = True
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, emitter = createIconTargets
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)
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env.Append(BUILDERS = {'IconRender' : buildIcon})
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def register_LumieraResourceBuilders(env):
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""" Registers further Custom Methods for installing various Resources.
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"""
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def IconResource(env, source):
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""" copy icon pixmap to corresponding icon dir. """
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subdir = getDirname(str(source))
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toBuild = env.path.buildIcon+subdir
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toInstall = env.path.installIcon+subdir
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env.Install (toInstall, source)
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return env.Install(toBuild, source)
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def GuiResource(env, source):
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""" pick up given source resource and install
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them (flat) into the configured target
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"""
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toBuild = env.path.buildUIRes
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toInstall = env.path.installUIRes
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env.Install (toInstall, source)
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return env.Install(toBuild, source)
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def ConfigData(env, prefix, source, targetDir=None):
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""" install (copy) configuration- and metadata.
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@param targetDir: when None, then use he install location configured (in Setup.py),
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otherwise an explicitly given absolute or relative path segment,
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which might refer to the location of the executable through the $ORIGIN token
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@param prefix: a prefix relative to the current path (location of SConscript),
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i.e. typically a subdirectory where to find the source config file
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"""
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source = path.join(prefix,str(source))
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subdir = getDirname(source, prefix) # removes source location path prefix
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if targetDir:
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if path.isabs(targetDir):
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toBuild = toInstall = path.join(targetDir,subdir)
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else:
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if targetDir.startswith('$ORIGIN'):
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targetDir = targetDir[len('$ORIGIN'):]
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toBuild = path.join(env.path.buildExe, targetDir, subdir)
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toInstall = path.join(env.path.installExe, targetDir, subdir)
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else:
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toBuild = path.join(env.path.buildConf, targetDir, subdir)
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toInstall = path.join(env.path.installConf, targetDir, subdir)
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else:
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toBuild = path.join(env.path.buildConf,subdir)
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toInstall = path.join(env.path.installConf,subdir)
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env.Install (toInstall, source)
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return env.Install(toBuild, source)
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def DocFile(env, prefix, source, target=None):
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""" install (copy) files for documentation.
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Always places the documentation below the standard location 'installDoc' configured in Setup.py
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@param prefix: relative to current path (SConscript), will be stripped at destination
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@param target: when given, the target will be named explicitly, or (when only a directory)
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placed into a specific subdir, otherwise (when None) the source spec will be placed
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into the corresponding subdir after stripping the prefix
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"""
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source = path.join(prefix,str(source))
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subdir = getDirname(source, prefix) # removes source location path prefix
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if not target:
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target = subdir+'/'
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elif target.endswith('/'):
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target = target+subdir+'/'
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toInstall = path.join(env.path.installDoc, target)
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if toInstall.endswith('/'):
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return env.Install(toInstall, source)
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else:
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return env.InstallAs(toInstall, source) # this renames at target
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env.AddMethod(IconResource)
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env.AddMethod(GuiResource)
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env.AddMethod(ConfigData)
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env.AddMethod(DocFile)
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class WrappedStandardExeBuilder(SCons.Util.Proxy):
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""" Helper to add customisations and default configurations to SCons standard builders.
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The original builder object is wrapped and most calls are simply forwarded to this
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wrapped object by Python magic. But some calls are intercepted in order to inject
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suitable default configuration based on the project setup.
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"""
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def __init__(self, originalBuilder):
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SCons.Util.Proxy.__init__ (self, originalBuilder)
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def __bool__(self): return True
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def __call__(self, env, target=None, source=None, **kw):
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""" when the builder gets invoked from the SConscript...
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create a clone environment for specific configuration
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and then pass on the call to the wrapped original builder.
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Automatically define installation targets for build results.
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@note only returning the build targets, not the install targets
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"""
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customisedEnv = self.getCustomEnvironment(env, target=target, **kw) # defined in subclasses
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buildTarget = self.buildLocation(customisedEnv, target)
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buildTarget = self.invokeOriginalBuilder(customisedEnv, buildTarget, source, **kw)
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self.installTarget(customisedEnv, buildTarget, **kw)
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return buildTarget
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def invokeOriginalBuilder(self, env, target, source, **kw):
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return self.get().__call__ (env, target, source, **kw)
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def buildLocation(self, env, target):
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""" prefix project output directory """
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prefix = self.getBuildDestination(env)
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return list(prefix+str(name) for name in target)
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def installTarget(self, env, buildTarget, **kw):
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""" create an additional installation target
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for the generated executable artifact
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"""
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indeedInstall = lambda p: p and p.get('install')
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if indeedInstall(kw):
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return env.Install (dir = self.getInstallDestination(env), source=buildTarget)
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else:
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return []
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class LumieraExeBuilder(WrappedStandardExeBuilder):
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def getCustomEnvironment(self, lumiEnv, **kw):
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""" augments the built-in Program() builder to add a fixed rpath based on $ORIGIN
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That is: after searching LD_LIBRARY_PATH, but before the standard linker search,
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the directory relative to the position of the executable ($ORIGIN) is searched.
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This search path is active not only for the executable, but for all libraries
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it is linked with.
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@note: enabling the new ELF dynamic tags. This causes a DT_RUNPATH to be set,
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which results in LD_LIBRARY_PATH being searched *before* the RPATH
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"""
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custEnv = lumiEnv.Clone()
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custEnv.Append( LINKFLAGS = "-Wl,-rpath=\\$$ORIGIN/modules,--enable-new-dtags" )
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if 'addLibs' in kw:
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custEnv.Append(LIBS = kw['addLibs'])
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return custEnv
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def getBuildDestination(self, lumiEnv): return lumiEnv.path.buildExe
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def getInstallDestination(self, lumiEnv): return lumiEnv.path.installExe
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class LumieraModuleBuilder(WrappedStandardExeBuilder):
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def getCustomEnvironment(self, lumiEnv, target, **kw):
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""" augments the built-in SharedLibrary() builder to add some tweaks missing in SCons 1.0,
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like setting a SONAME proper instead of just passing the relative pathname to the linker.
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Besides, we override the library search path to allow for transitive dependencies between
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Lumiera modules; modules are assumed to reside in a subdirectory below the executable.
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"""
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custEnv = lumiEnv.Clone()
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custEnv.Append( LINKFLAGS = "-Wl,-soname="+self.defineSoname(target,**kw))
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custEnv.Append( LINKFLAGS = "-Wl,-rpath=\\$$ORIGIN/../modules,--enable-new-dtags" )
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if 'addLibs' in kw:
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custEnv.Append(LIBS = kw['addLibs'])
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return custEnv
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def getBuildDestination(self, lumiEnv): return lumiEnv.path.buildLib
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def getInstallDestination(self, lumiEnv): return lumiEnv.path.installLib
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def installTarget(self, env, buildTarget, **kw):
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""" ensure a shared library is not marked executable.
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The default toolchain on Linux often installs shared libraries as executable, which seems
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to be necessary on some arcane Unix platforms. However, Debian Policy prohibits that.
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See https://unix.stackexchange.com/questions/400187/why-should-or-should-not-shared-libraries-be-executable-e-g-red-hat-vs-debian
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"""
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toInstall = super().installTarget(env, buildTarget, **kw)
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if toInstall:
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def _Chmod(target, source, env):
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""" Workaround since env.Chmod is present only in SCons 4.10 """
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import os
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for t in target:
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os.chmod(str(t), 0o644)
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return None
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# removeExecBit = env.Chmod(toInstall, 0o644) # ◁◁◁ could use this for SCons > 4.10
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msg = '....... clear exec perm %s' % [str(t) for t in toInstall]
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removeExecBit = env.Action(_Chmod, msg)
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env.AddPostAction(toInstall, removeExecBit)
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return toInstall
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def defineSoname (self, target, **kw):
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""" internal helper to extract or guess
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a suitable library SONAME, either using an
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explicit spec, falling back on the lib filename
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"""
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if 'soname' in kw:
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soname = self.subst(kw['soname']) # explicitly defined by user
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else: # else: use the library filename as DT_SONAME
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if SCons.Util.is_String(target):
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pathname = target.strip()
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elif 1 == len(target):
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pathname = str(target[0]).strip()
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else:
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raise SyntaxError("Lumiera Library builder requires exactly one target spec. Found target="+str(target))
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assert pathname
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(dirprefix, libname) = path.split(pathname)
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if not libname:
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raise ValueError("Library name missing. Only got a directory: "+pathname)
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soname = "${SHLIBPREFIX}%s$SHLIBSUFFIX" % libname
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assert soname
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return soname
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class LumieraPluginBuilder(LumieraModuleBuilder):
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def getCustomEnvironment(self, lumiEnv, target, **kw):
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""" in addition to the ModuleBuilder, define the Lumiera plugin suffix
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"""
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custEnv = LumieraModuleBuilder.getCustomEnvironment(self, lumiEnv, target, **kw)
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custEnv.Append (CPPDEFINES='LUMIERA_PLUGIN')
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custEnv.Replace(SHLIBPREFIX='', SHLIBSUFFIX='.lum')
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return custEnv
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def getBuildDestination(self, lumiEnv): return lumiEnv.path.buildPlug
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def getInstallDestination(self, lumiEnv): return lumiEnv.path.installPlug
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def register_LumieraCustomBuilders (lumiEnv):
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""" install the customised builder versions tightly integrated with our build system.
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Especially, these builders automatically add the build and installation locations
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and set the RPATH and SONAME in a way to allow a relocatable Lumiera directory structure
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"""
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programBuilder = LumieraExeBuilder (lumiEnv['BUILDERS']['Program'])
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libraryBuilder = LumieraModuleBuilder (lumiEnv['BUILDERS']['SharedLibrary'])
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smoduleBuilder = LumieraModuleBuilder (lumiEnv['BUILDERS']['LoadableModule'])
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lpluginBuilder = LumieraPluginBuilder (lumiEnv['BUILDERS']['LoadableModule'])
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lumiEnv['BUILDERS']['Program'] = programBuilder
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lumiEnv['BUILDERS']['SharedLibrary'] = libraryBuilder
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lumiEnv['BUILDERS']['LoadableModule'] = smoduleBuilder
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lumiEnv['BUILDERS']['LumieraPlugin'] = lpluginBuilder
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def SymLink(env, target, source, linktext=None):
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""" use python to create a symlink
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"""
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def makeLink(target,source,env):
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if linktext:
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dest = linktext
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else:
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dest = str(source[0])
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link = str(target[0])
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os.symlink(dest, link)
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if linktext: srcSpec=linktext
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else: srcSpec='$SOURCE'
|
||
action = Action(makeLink, "Install link: $TARGET -> "+srcSpec)
|
||
env.Command (target,source, action)
|
||
|
||
# adding SymLink directly as method on the environment object
|
||
# Probably that should better be a real builder, but I couldn't figure out
|
||
# how to get the linktext through literally, which is necessary for relative links.
|
||
# Judging from the sourcecode of SCons.Builder.BuilderBase, there seems to be no way
|
||
# to set the executor_kw, which are passed through to the action object.
|
||
lumiEnv.AddMethod(SymLink)
|