Add basic configuration API.

examples/config/fabscript

@@ -0,0 +1,60 @@
+# -*- python -*-
+#
+# Copyright (c) 2016 Stefan Seefeld
+# All rights reserved.
+#
+# This file is part of Faber. It is made available under the
+# Boost Software License, Version 1.0.
+# (Consult LICENSE or http://www.boost.org/LICENSE_1_0.txt)
+
+#
+# This example demonstrates how to configure a project.
+#
+# Run with:
+#
+#   * `faber cxxflags=-I/usr/include/python2.7 libs=python2.7`
+#   * `faber cxxflags=-std=c++14`
+#   * `faber --with-python-inc=/usr/include/python2.7 --with-python-lib=python2.7`
+#
+# To remove config artefacts run with:
+#
+#   * `faber .config-clean`
+
+from faber.artefacts.binary import binary
+from faber.tools.compiler import define, include, linkpath, libs
+from faber.types import cxx, c
+from faber.config.try_link import *
+from faber.config import report, c_checks, cxx_checks, try_run
+from faber import scheduler
+
+python_inc = options.get_with('python-inc')
+python_linkpath = options.get_with('python-linkpath')
+python_lib = options.get_with('python-lib')
+if python_inc:
+    features |= include(python_inc)
+if python_linkpath:
+    features |= linkpath(python_linkpath)
+if python_lib:
+    features |= libs(python_lib)
+
+pysrc="""
+#include <Python.h>
+int main()
+{
+  Py_Initialize();
+}
+"""
+checks = [c_checks.sizeof('char', cxx, features=features),
+          c_checks.sizeof('long', cxx, features=features),
+          try_link('pytest', pysrc, cxx, features,
+                   define('HAS_PYTHON=1'),
+                   define('HAS_PYTHON=0')),
+          cxx_checks.has_cxx11(features, define('HAS_CXX11')),
+          cxx_checks.has_cxx14(features, define('HAS_CXX14')),
+          cxx_checks.has_cxx17(features, define('HAS_CXX17'))]
+
+config = report('config', checks)
+bin = binary('check', 'main.cpp', dependencies=config, features=config.use)
+report = rule(action('run', '$(>)'), 'report', bin, attrs=notfile|always)
+
+default = report

examples/config/main.cpp

@@ -0,0 +1,35 @@
+//
+// Copyright (c) 2016 Stefan Seefeld
+// All rights reserved.
+//
+// This file is part of Faber. It is made available under the
+// Boost Software License, Version 1.0.
+// (Consult LICENSE or http://www.boost.org/LICENSE_1_0.txt)
+
+#include <iostream>
+
+#ifdef HAS_CXX11
+# define cxx11 "defined"
+#else
+# define cxx11 "undefined"
+#endif
+#ifdef HAS_CXX14
+# define cxx14 "defined"
+#else
+# define cxx14 "undefined"
+#endif
+#ifdef HAS_CXX17
+# define cxx17 "defined"
+#else
+# define cxx17 "undefined"
+#endif
+
+
+int main()
+{
+    std::cout << "HAS_PYTHON=" << HAS_PYTHON << '\n'
+	      << "HAS_CXX11 " << cxx11 << '\n'
+	      << "HAS_CXX14 " << cxx14 << '\n'
+	      << "HAS_CXX17 " << cxx17 << '\n'
+	      << std::endl;
+}

src/faber/config/__init__.py

@@ -0,0 +1,32 @@
+#
+# Copyright (c) 2016 Stefan Seefeld
+# All rights reserved.
+#
+# This file is part of Faber. It is made available under the
+# Boost Software License, Version 1.0.
+# (Consult LICENSE or http://www.boost.org/LICENSE_1_0.txt)
+
+from ..artefact import artefact, notfile
+from ..rule import depend
+from .. import output
+
+
+class report(artefact):
+
+    def __init__(self, name, checks):
+        use = [c.use for c in checks]
+        artefact.__init__(self, name, attrs=notfile, use=use)
+        depend(self, checks)
+        self.checks = checks
+
+    def _report(self):
+
+        max_name_length = max(len(c.qname) for c in self.checks)
+        print(output.coloured('configuration check results:', attrs=['bold']))
+        for c in self.checks:
+            print('  {:{}} : {} {}'
+                  .format(c.qname, max_name_length, c.result, '(cached)' if c.cached else ''))
+
+    def __status__(self, status):
+        artefact.__status__(self, status)
+        self._report()

src/faber/config/c_checks.py

@@ -0,0 +1,23 @@
+#
+# Copyright (c) 2016 Stefan Seefeld
+# All rights reserved.
+#
+# This file is part of Faber. It is made available under the
+# Boost Software License, Version 1.0.
+# (Consult LICENSE or http://www.boost.org/LICENSE_1_0.txt)
+
+from .try_run import check_output
+from .. import types
+
+
+class sizeof(check_output):
+
+    src = """#include <stdio.h>
+int main(){{ printf("%i", sizeof({}));}}"""
+
+    def __init__(self, c_type, lang_type=types.c, features=()):
+        check_output.__init__(self, 'sizeof_' + c_type, sizeof.src.format(c_type), lang_type,
+                              features)
+
+    def post_process(self, output):
+        self.result = int(output)

src/faber/config/check.py

@@ -0,0 +1,92 @@
+#
+# Copyright (c) 2016 Stefan Seefeld
+# All rights reserved.
+#
+# This file is part of Faber. It is made available under the
+# Boost Software License, Version 1.0.
+# (Consult LICENSE or http://www.boost.org/LICENSE_1_0.txt)
+
+from ..feature import conditional
+from ..artefact import artefact, notfile, nocare
+from ..module import module
+import sqlite3
+import hashlib
+import os
+import os.path
+import logging
+
+logger = logging.getLogger('config')
+
+
+class cache(object):
+
+    def __init__(self):
+        if not os.path.exists(module.current.builddir):
+            os.makedirs(module.current.builddir)
+        self.filename = os.path.join(module.current.builddir, '.configcache')
+        self.conn = sqlite3.connect(self.filename)
+        # Create table if it doesn't exist yet.
+        if not next(self.conn.execute('SELECT name FROM sqlite_master '
+                                      'WHERE type="table" AND name="checks"'), None):
+            self.conn.execute('CREATE TABLE checks '
+                              '(key TEXT, status INTEGER, type TEXT, value TEXT)')
+
+    def __del__(self):
+        self.conn.commit()
+
+    def clean(self):
+        self.conn.close()
+        os.remove(self.filename)
+        del self
+
+    def __contains__(self, key):
+        with self.conn:
+            a = self.conn.execute('SELECT key FROM checks WHERE key=?', (key,))
+        value = next(a, None)
+        return bool(value)
+
+    def __setitem__(self, key, value):
+        status, result = value[0], value[1]
+        with self.conn:
+            self.conn.execute('INSERT INTO checks VALUES(?,?,?,?)',
+                              (key, status, type(result).__name__, str(result)))
+
+    def __getitem__(self, key):
+        with self.conn:
+            a = self.conn.execute('SELECT status, type, value FROM checks WHERE key=?',
+                                  (key,))
+        status, type, value = next(a, (None, None, None))
+        value = {'str': lambda x: x,
+                 'unicode': lambda x: x,
+                 'bool': lambda x: eval(x),
+                 'int': lambda x: int(x)}[type](value)
+        return status, value
+
+
+class check(artefact):
+    """A check is an artefact that performs some tests (typically involving compilation),
+    then stores the result in a cache, so it doesn't need to be performed again,
+    until the cache is explicitly cleared."""
+
+    cache = cache() if module.current else None  # to support sphinx' autoclass
+
+    def __init__(self, name, features=(), if_=(), ifnot=()):
+
+        self.result = None
+        artefact.__init__(self, name, attrs=notfile|nocare, features=features)
+        # The 'condition' here is simply the value of the check's status member.
+        self.use = conditional(lambda ctx: self.status, self, if_, ifnot)
+        key = str((self.name, str(self.features))).encode('utf-8')
+        self._cache_key = hashlib.md5(key).hexdigest()
+        self.cached = self._cache_key in check.cache
+        if self.cached:
+            self.status, self.result = check.cache[self._cache_key]
+
+    def __status__(self, status):
+        logger.debug('check.__status__({})'.format(status))
+        if self.cached:
+            return  # the cached value takes precedence
+        artefact.__status__(self, status)
+        if not self.status or self.result is None:
+            self.result = self.status
+        check.cache[self._cache_key] = (self.status, self.result)

src/faber/config/cxx_checks.py

@@ -0,0 +1,43 @@
+#
+# Copyright (c) 2016 Stefan Seefeld
+# All rights reserved.
+#
+# This file is part of Faber. It is made available under the
+# Boost Software License, Version 1.0.
+# (Consult LICENSE or http://www.boost.org/LICENSE_1_0.txt)
+
+from .try_compile import try_compile
+from .. import types
+
+
+class has_cxx11(try_compile):
+
+    src = r"""#if __cplusplus < 201103L
+#error no C++11
+#endif"""
+
+    def __init__(self, features=(), if_=(), ifnot=()):
+        try_compile.__init__(self, 'has_cxx11', has_cxx11.src, types.cxx, features,
+                             if_, ifnot)
+
+
+class has_cxx14(try_compile):
+
+    src = r"""#if __cplusplus < 201402L
+#error no C++14
+#endif"""
+
+    def __init__(self, features=(), if_=(), ifnot=()):
+        try_compile.__init__(self, 'has_cxx14', has_cxx14.src, types.cxx, features,
+                             if_, ifnot)
+
+
+class has_cxx17(try_compile):
+
+    src = r"""#if __cplusplus < 201500L
+#error no C++17
+#endif"""
+
+    def __init__(self, features=(), if_=(), ifnot=()):
+        try_compile.__init__(self, 'has_cxx17', has_cxx17.src, types.cxx, features,
+                             if_, ifnot)

src/faber/config/try_compile.py

@@ -0,0 +1,32 @@
+#
+# Copyright (c) 2016 Stefan Seefeld
+# All rights reserved.
+#
+# This file is part of Faber. It is made available under the
+# Boost Software License, Version 1.0.
+# (Consult LICENSE or http://www.boost.org/LICENSE_1_0.txt)
+
+from .check import check
+from ..artefact import intermediate, always
+from ..tools.compiler import compiler
+from ..rule import rule, alias
+from ..artefacts.object import object
+
+
+class try_compile(check):
+    """Try to compile a chunk of source code."""
+
+    def __init__(self, name, source, type, features=(), if_=(), ifnot=()):
+
+        check.__init__(self, name, features, if_, ifnot)
+        compiler.check_instance_for_type(type, features)
+        if not self.cached:
+            # create source file
+            src = type.synthesize_name(self.name)
+
+            def generate(targets, _):
+                with open(targets[0]._filename, 'w') as os:
+                    os.write(source)
+            src = rule(generate, src, attrs=intermediate|always)
+            obj = object(self.name, src, attrs=intermediate, features=self.features)
+            alias(self, obj)

src/faber/config/try_link.py

@@ -0,0 +1,32 @@
+#
+# Copyright (c) 2016 Stefan Seefeld
+# All rights reserved.
+#
+# This file is part of Faber. It is made available under the
+# Boost Software License, Version 1.0.
+# (Consult LICENSE or http://www.boost.org/LICENSE_1_0.txt)
+
+from .check import check
+from ..artefact import intermediate, always
+from ..tools.compiler import compiler
+from ..rule import rule, alias
+from ..artefacts.binary import binary
+
+
+class try_link(check):
+    """Try to compile and link a chunk of source code."""
+
+    def __init__(self, name, source, type, features=(), if_=(), ifnot=()):
+
+        check.__init__(self, name, features, if_, ifnot)
+        compiler.check_instance_for_type(type, features)
+        if not self.cached:
+            # create source file
+            src = type.synthesize_name(self.name)
+
+            def generate(targets, _):
+                with open(targets[0]._filename, 'w') as os:
+                    os.write(source)
+            src = rule(generate, src, attrs=intermediate|always)
+            bin = binary(self.name, src, attrs=intermediate, features=self.features)
+            alias(self, bin)