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SCons / MakeBuilder

Here is a Builder that runs make. It's intended to be used along with UnTarBuilder and AutoConfigBuilder to extract some source code, configure it, and build it.

The Builder accepts several options to control build targets, execution environment, and make command-line options. It will also pass the SCons -j parameter to the make command (but there's an option to prevent that).

Table of Contents

Definition

#!python 

# Make Builder: Runs make.
#
# Parameters:
#    MakePath -- SCons Dir node representing the directory in which to run make.  REQUIRED.
#    MakeCmd -- The 'make' executable to run.
#               Default: make
#    MakeEnv -- Dictionary of variables to set in the make execution environment.
#               Default: none
#    MakeOpts -- Options to pass on the make command line.
#                Default: none
#    MakeOneThread -- Don't pass any -j option to make.
#                     Default: False
#    MakeTargets -- String of space-seperated targets to pass to make
#                   Default: ""

import os
import subprocess

from SCons.Script import *

def parms(target, source, env):
    """Assemble various Make parameters."""

    if 'MakePath' in env.Dictionary().keys():
        make_path = env.subst(str(env['MakePath']))
    else:
        print "Make builder requires MakePath variable"
        Exit(1)

    make_cmd = 'make'
    if 'MakeCmd' in env.Dictionary().keys():
        make_cmd = env.subst(env['MakeCmd'])
    elif 'MAKE' in env.Dictionary().keys():
        make_cmd = env.subst(env['MAKE'])

    make_env = None
    if env['CROSS_BUILD']:
        make_env = env['CROSS_ENV']
    if 'MakeEnv' in env.Dictionary().keys():
        if make_env == None:
            make_env = {}
        else:
            # We're appending to an existing dictionary, so create a copy
            # instead of appending to the original env['CROSS_ENV']
            make_env = env['CROSS_ENV'][:]
        for (k,v) in env['MakeEnv'].items():
            make_env[k] = v

    make_opts = None
    if 'MakeOpts' in env.Dictionary().keys():
        make_opts = env.subst(env['MakeOpts'])

    make_jobs = GetOption('num_jobs')
    if 'MakeOneThread' in env.Dictionary().keys() and env['MakeOneThread']:
        make_jobs = 1

    make_targets = None
    if 'MakeTargets' in env.Dictionary().keys():
        make_targets = env.subst(env['MakeTargets'])

    return (make_path, make_env, make_targets, make_cmd, make_jobs, make_opts)

def message(target, source, env):
    """Return a pretty Make message"""

    (make_path,
     make_env,
     make_targets,
     make_cmd,
     make_jobs,
     make_opts) = parms(target, source, env)

    myenv = env.Clone()
    # Want to use MakeTargets in the MAKECOMSTR, but make it pretty first.
    if 'MakeTargets' in myenv.Dictionary().keys():
        myenv['MakeTargets'] += ' '
    else:
        myenv['MakeTargets'] = ''

    if 'MAKECOMSTR' in myenv.Dictionary().keys():
        return myenv.subst(myenv['MAKECOMSTR'],
                            target = target, source = source, raw = 1)

    msg = 'cd ' + make_path + ' &&'
    if make_env != None:
        for k, v in make_env.iteritems():
            msg += ' ' + k + '=' + v
    msg += ' ' + make_cmd
    if make_jobs > 1:
        msg += ' -j %d' % make_jobs
    if make_opts != None:
        msg += ' ' + ' '.join(make_opts)
    if make_targets != None:
        msg += ' ' + make_targets
    return msg

def builder(target, source, env):
    """Run make in a directory."""

    (make_path,
     make_env,
     make_targets,
     make_cmd,
     make_jobs,
     make_opts) = parms(target, source, env)

    # Make sure there's a directory to run make in
    if len(make_path) == 0:
        print 'No path specified'
    if not os.path.exists(make_path):
        print 'Path %s not found' % make_path

    # Build up the command and its arguments in a list
    fullcmd = [ make_cmd ]

    if make_jobs > 1:
        fullcmd += [ '-j', str(make_jobs) ]

    if make_opts:
        fullcmd += make_opts

    if make_targets:
        fullcmd += make_targets.split()

    # Capture the make command's output, unless we're verbose
    real_stdout = subprocess.PIPE
    if 'MAKECOMSTR' not in env.Dictionary().keys():
        real_stdout = None

    # Make!
    make = subprocess.Popen(fullcmd,
                            cwd = make_path,
                            stdout = real_stdout,
                            env = make_env)

    # Some subprocesses don't terminate unless we communicate with them
    output = make.communicate()[0]
    return make.returncode

def generate(env, **kwargs):
    env['BUILDERS']['Make'] = env.Builder(
        action = env.Action(builder, message))

def exists(env):
    if env.WhereIs(env.subst('$MAKE')) != None:
        return True
    return False

Installation

To load this Builder into your environment, save the above as Make.py in your site_scons/site_tools/ directory, then add it as a tool to your environment:

#!python 
env = Environment(tools = ['default', 'Make'])
# or
otherenv.Tool('Make')

Usage

You use this builder by giving it source and target parameters as usual, but also specifying MakePath to tell it in which directory to run make.

#!python 
# Define the sources for the make build, so SCons can track dependencies
# (or just set source=None to have SCons run make all the time and
# let make track dependencies).
src = Glob('foo-1.2.3/*.c')

# Run make inside the foo-1.2.3/ directory
foolib = env.Make(source = src,
                  target = [ 'foo-1.2.3/.libs/libfoo.a',
                             'foo-1.2.3/.libs/libfoo.so' ],
                  MakePath = Dir('foo-1.2.3'))

If your environment has MAKECOMSTR defined, the builder uses that string to print its command message and also hides the command's output. Without MAKECOMSTR the builder prints the full make command as well as the command's output.

Parameters

  • MakePath -- (Required) SCons Dir node representing the directory in which to run make.

  • MakeCmd -- (Default: make) The 'make' executable to run.

  • MakeEnv -- (Default: none) Dictionary of variables to set in the make execution environment.

  • MakeOpts -- (Default: none) Options to pass on the make command line.

  • MakeOneThread -- (Default: False) Don't pass any -j options to make.

  • MakeTargets -- (Default: none) String of space-separated targets for make to build.

Updated