我写了一个python函数,比如替换字符串,并在scons脚本中调用.
def Replace(env,filename,old,new):
with open(filename,"r+") as f:
d = f.read()
d = d.replace(old,new)
f.truncate(0)
f.seek(0)
f.write(d)
f.close()
env.AddMethod(Replace,'Replace')
在SConscript中
lib = env.SharedLibrary('lib',object,extra_libs)
tmp = env.Command([],[],[env.Replace(somefile,'A','b')] )
env.Depends(tmp,lib )
我期望在lib构建之后运行Replace()方法.
但是scons总是在第一轮脚本解析短语中运行Replace().
似乎我错过了一些依赖.
最佳答案
我相信你可能正在寻找builders that execute python functions.
棘手的一点是,SCons并不真的想以你强迫它的方式工作.构建操作应该是可重复且非破坏性的,在您的代码中,您实际上正在破坏某些文件的原始内容.相反,您可以使用目标/源范例和某种模板文件来实现相同的结果.
import os
import re
def replace_action(target,source,env):
# NB. this is a pretty sloppy way to write a builder,but
# for things that are used internally or infrequently
# it should be more than sufficient
assert( len(target) == 1 )
assert( len(source) == 1 )
srcf = str(source[0])
dstf = str(target[0])
with open(srcf,"r") as f:
contents = f.read()
# In cases where this builder fails,check to make sure you
# have correctly added REPLST to your environment
for old,new in env['REPLST']:
contents = re.sub( old,new,contents )
with open( dstf,"w") as outf:
outf.write(contents)
replace_builder = Builder(action = replace_action)
env = Environment( ENV = os.environ )
env.Append( BUILDERS = {'Replace' : replace_builder } )
b = env.Replace( 'somefile',['somefile.tmpl'],REPLST=[('A','b')] )
lib = env.SharedLibrary('lib',object + [b],extra_libs )
请注意,在我的测试中,替换函数与多行数据不能很好地协作,所以我只是交换使用完整的正则表达式(re.sub).这可能比较慢,但提供了更大的灵活性.