Question

我是scons的新手，我遇到了scons dependancies的问题在使用变体目录的层次结构构建中。

我能够在包含的简化环境中重现问题 SConscript目录下的2个子目录（moduleA和moduleB）如下：

.
|-- SConstruct
|-- file.conf
|-- moduleA
|   |-- SConscript
|   `-- conf2cc
`-- moduleB
    |-- SConscript
    `-- fileB.cc

以下是需要完成的工作流程：

moduleA执行shell脚本：conf2cc，输入：$ projRootDir / file.conf，output：moduleA / $ variantDir / source.cc
moduleA编译source.cc并创建moduleA / $ variantDir / libmoduleA.a
moduleB需要将moduleA / $ variantDir / source.cc复制到moduleB / source.cc
moduleB需要将moduleB / source.cc和moduleB / fileB.cc编译到其中 library libmoduleB.a

我完全有可能在这里犯了几件错事。例如，我知道我没有在moduleA Command（）中使用$ TARGET / $ SOURCE，但这是故意的，因为脚本需要绝对路径名，而scons不会删除前导'＃'

我遇到的问题是moduleB中的Command（）构建器（上面的步骤3）从不执行。

以下是SConstruct和SConscript文件：

Sconstruct

import os

env = Environment()
env['variantDir'] = 'linux'  # for this example, just make variantDir = linux
modules = ['moduleA', 'moduleB']

for dir in modules:
    SConscript(
        os.path.join(dir, 'SConscript'),
        variant_dir = os.path.join(dir, env['variantDir']),
        exports = ['env'],
        duplicate = 0)

moduleA / Sconscript

import os

Import('env')

scriptInput   = '#file.conf'
sourceFile    = os.path.join('#moduleA', env['variantDir'],  'source.cc')
conf2ccScript = File('#moduleA/conf2cc').abspath

# The script needs abspaths for input and output, not the scons '#' prepended
# the script syntax is: script <inputFile> <outputFile>
cmd = '%s %s %s' % (conf2ccScript, File(scriptInput).abspath, File(sourceFile).abspath)

# Generate source.cc file based on file.conf
conf2ccNode = env.Command(target = sourceFile,
                          source = scriptInput,
                          action = cmd)

libNode = env.Library(target = 'moduleA', source = sourceFile)
env.Depends(libNode, conf2ccNode)

moduleB / Sconscript

import os

Import('env')

sourceFiles = ['fileB.cc', 'source.cc']

# Get the source.cc file
externalSourceFile  = os.path.join('#moduleA', env['variantDir'], 'source.cc')
sourceTarget        = os.path.join('#moduleB', 'source.cc')

cmdNode = env.Command(target = sourceTarget,
                      source = externalSourceFile,
                      action = Copy('$TARGET', '$SOURCE'))

libNode = env.Library(target = 'moduleB', source = sourceFiles)
env.Depends(libNode, cmdNode)

这是我执行scons时的输出：

非常感谢任何帮助！

贝迪

notroot@ubuntu:~/projects/sconsTest/sconsTestHierDeps$ scons
scons: Reading SConscript files ...
scons: done reading SConscript files.
scons: Building targets ...
/home/notroot/projects/sconsTest/sconsTestHierDeps/moduleA/conf2cc /home/notroot/projects/sconsTest/sconsTestHierDeps/file.conf /home/notroot/projects/sconsTest/sconsTestHierDeps/moduleA/linux/source.cc
g++ -o moduleA/linux/source.o -c moduleA/linux/source.cc
ar rc moduleA/linux/libmoduleA.a moduleA/linux/source.o
ranlib moduleA/linux/libmoduleA.a
g++ -o moduleB/linux/fileB.o -c moduleB/fileB.cc
scons: *** [moduleB/linux/source.o] Source `moduleB/source.cc' not found, needed by target `moduleB/linux/source.o'.
scons: building terminated because of errors.

Answer 1

我找到了问题的解决方案，但我真的不明白为什么会有效。

如果我使用我需要构建的目标添加对env.Default（）的调用，那么它可以工作。所以SConscript文件看起来像这样：

moduleA / Sconscript

import os

Import('env')

scriptInput   = '#file.conf'
sourceFile    = os.path.join('#moduleA', env['variantDir'],  'source.cc')
conf2ccScript = File('#moduleA/conf2cc').abspath

# The script needs abspaths for input and output, not the scons '#' prepended
# the script syntax is: script <inputFile> <outputFile>
cmd = '%s %s %s' % (conf2ccScript, File(scriptInput).abspath, File(sourceFile).abspath)

# Generate source.cc file based on file.conf
conf2ccNode = env.Command(target = sourceFile,
                          source = scriptInput,
                          action = cmd)

libNode = env.Library(target = 'moduleA', source = sourceFile)
env.Depends(libNode, conf2ccNode)
env.Default([conf2ccNode, libNode])

moduleB / Sconscript

import os

Import('env')

sourceFiles = ['fileB.cc', 'source.cc']

# Get the source.cc file
externalSourceFile  = os.path.join('#moduleA', env['variantDir'], 'source.cc')
sourceTarget        = os.path.join('#moduleB', 'source.cc')

cmdNode = env.Command(target = sourceTarget,
                      source = externalSourceFile,
                      action = Copy('$TARGET', '$SOURCE'))

libNode = env.Library(target = 'moduleB', source = sourceFiles)
env.Depends(libNode, cmdNode)
env.Default(cmdNode, libNode)

这就引出了一个问题：如果我没有指定Default（）目标并且有多个目标，那么scons如何知道要构建哪个目标？

另外，我仍然不明白为什么scons没有解决libNode在cmdNode上的moduleB / SConscript中的依赖性。

Answer 2

我建议使用不正确的依赖项和文件名。

可能是variant_dir和moduleB的源文件有问题，你使用Command来生成＃/ moduleB / source.cc，但是在sourceFiles中你有'source.cc'。

所以，帮助你的方法之一可能是正确的moduleB SConscript：

# Get the source.cc file
externalSourceFile  = os.path.join('#moduleA', env['variantDir'], 'source.cc')
sourceTarget        = os.path.join('#moduleB', 'source.cc')

sourceFiles = ['fileB.cc', sourceTarget]

cmdNode = env.Command(target = sourceTarget,
                      source = externalSourceFile,
                      action = Copy('$TARGET', '$SOURCE'))

libNode = env.Library(target = 'moduleB', source = sourceFiles)

并尝试使用Command之类的源文件。而是文件名。它看起来更正确。 moduleA：

conf2ccNode = env.Command(target = sourceFile,
                          source = scriptInput,
                          action = cmd)
libNode = env.Library(target = 'moduleA', source = conf2ccNode)

moduleB：

cmdNode = env.Command(target = sourceTarget,
                      source = externalSourceFile,
                      action = Copy('$TARGET', '$SOURCE'))

libNode = env.Library(target = 'moduleB', source = ['fileB.cc', cmdNode])

Answer 3

我的解决方案：

def CreateLibrary(env, name, sources, shared=True):

    def GetObjectFile(sourceFileName):

        def GetFileNameWithoutExtension(path):
            return os.path.splitext(os.path.basename(path))[0]

        def IsFileNameExist(newFileName):
            return fileNames.count(newFileName) > 0

        sourceAbsPath = os.path.abspath(sourceFileName)
        fileNameWithoutExtension = GetFileNameWithoutExtension(sourceAbsPath)
        destFileName = fileNameWithoutExtension
        attemptNumber = 0
        while IsFileNameExist(destFileName):
            attemptNumber += 1
            destFileName = fileNameWithoutExtension + str(attemptNumber)
        fileNames.append(destFileName)
        destFilePath = os.path.join(compilationDirRoot, destFileName)
        if shared:
            return env.SharedObject(destFilePath, sourceAbsPath)
        else:
            return env.StaticObject(destFilePath, sourceAbsPath)

    objFiles = []
    fileNames = []
    compilationDirRoot = Dir('.').abspath
    for src in sources:
        if isinstance(src,str):
            objFiles.append(GetObjectFile(src))
        elif isinstance(src, SCons.Node.FS.File):
            objFiles.append(GetObjectFile(SCons.Node.FS.File.rstr(src)))
        else:
            for f in src:
                objFiles.append(GetObjectFile(str(f)))
    if shared:
        return env.SharedLibrary(name, objFiles, no_import_lib=True)
    else:
        return env.StaticLibrary(name, objFiles)

使用示例：

theora = CreateLibrary(env, 'theora', sources)

使用变量dirs进行分层构建时的scons依赖问题

3 个答案: