[build-script] Introduce ProductBuilder. Transform Ninja to use it.

utils/build-script

@@ -444,11 +444,12 @@ class BuildScriptInvocation(object):
                 "can't find source directory for ninja "
                 "(tried %s)" % (self.workspace.source_dir("ninja")))
 
-        ninja_build = products.Ninja(
+        ninja_build = products.Ninja.new_builder(
             args=self.args,
             toolchain=self.toolchain,
-            source_dir=self.workspace.source_dir("ninja"),
-            build_dir=self.workspace.build_dir("build", "ninja"))
+            workspace=self.workspace,
+            host=StdlibDeploymentTarget.get_target_for_name(
+                self.args.host_target))
         ninja_build.build()
         self.toolchain.ninja = ninja_build.ninja_bin_path
 

utils/swift_build_support/swift_build_support/products/ninja.py

@@ -28,6 +28,20 @@ class Ninja(product.Product):
     def is_build_script_impl_product(cls):
         return False
 
+    @classmethod
+    def new_builder(cls, args, toolchain, workspace, host):
+        return NinjaBuilder(cls, args, toolchain, workspace)
+
+
+class NinjaBuilder(product.ProductBuilder):
+    def __init__(self, product_class, args, toolchain, workspace):
+        self.source_dir = workspace.source_dir(
+            product_class.product_source_name())
+        self.build_dir = workspace.build_dir('build',
+                                             product_class.product_name())
+        self.args = args
+        self.toolchain = toolchain
+
     @cache_util.reify
     def ninja_bin_path(self):
         return os.path.join(self.build_dir, 'ninja')

utils/swift_build_support/swift_build_support/products/product.py

@@ -10,6 +10,8 @@
 #
 # ----------------------------------------------------------------------------
 
+import abc
+
 
 class Product(object):
     @classmethod
@@ -58,3 +60,76 @@ def __init__(self, args, toolchain, source_dir, build_dir):
         self.source_dir = source_dir
         self.build_dir = build_dir
         self.cmake_options = []
+
+
+class ProductBuilder(object):
+    """
+    Abstract base class for all ProductBuilders.
+
+    An specific ProductBuilder will implement the interface methods depending
+    how the product want to be build. Multiple products can use the same
+    product builder if parametrized right (for example all the products build
+    using CMake).
+
+    Ideally a ProductBuilder will be initialized with references to the
+    invocation arguments, the calculated toolchain, the calculated workspace,
+    and the target host, but the base class doesn't impose those requirements
+    in order to be flexible.
+
+    NOTE: Python doesn't need an explicit abstract base class, but it helps
+    documenting the interface.
+    """
+
+    @abc.abstractmethod
+    def __init__(self, product_class, args, toolchain, workspace):
+        """
+        Create a product builder for the given product class.
+
+        Parameters
+        ----------
+        product_class : class
+            A subtype of `Product` which describes the product being built by
+            this builder.
+        args : `argparse.Namespace`
+            The arguments passed by the user to the invocation of the script. A
+            builder should consider this argument read-only.
+        toolchain : `swift_build_support.toolchain.Toolchain`
+            The toolchain being used to build the product. The toolchain will
+            point to the tools that the builder should use to build (like the
+            compiler or the linker).
+        workspace : `swift_build_support.workspace.Workspace`
+            The workspace where the source code and the build directories have
+            to be located. A builder should use the workspace to access its own
+            source/build directory, as well as other products source/build
+            directories.
+        """
+        pass
+
+    @abc.abstractmethod
+    def build(self):
+        """
+        Perform the build phase for the product.
+
+        This phase might also imply a configuration phase, but each product
+        builder is free to determine how to do it.
+        """
+        pass
+
+    @abc.abstractmethod
+    def test(self):
+        """
+        Perform the test phase for the product.
+
+        This phase might build and execute the product tests.
+        """
+        pass
+
+    @abc.abstractmethod
+    def install(self):
+        """
+        Perform the install phase for the product.
+
+        This phase might copy the artifacts from the previous phases into a
+        destination directory.
+        """
+        pass

utils/swift_build_support/tests/products/test_ninja.py

@@ -26,6 +26,7 @@
 from swift_build_support import shell
 from swift_build_support import xcrun
 from swift_build_support.products import Ninja
+from swift_build_support.targets import StdlibDeploymentTarget
 from swift_build_support.toolchain import host_toolchain
 from swift_build_support.workspace import Workspace
 
@@ -41,6 +42,8 @@ def setUp(self):
         self.workspace = Workspace(source_root=tmpdir1,
                                    build_root=tmpdir2)
 
+        self.host = StdlibDeploymentTarget.host_target()
+
         # Setup toolchain
         self.toolchain = host_toolchain()
         self.toolchain.cc = '/path/to/cc'
@@ -71,20 +74,23 @@ def tearDown(self):
         self.args = None
 
     def test_ninja_bin_path(self):
-        ninja_build = Ninja(
+        ninja_build = Ninja.new_builder(
             args=self.args,
             toolchain=self.toolchain,
-            source_dir='/path/to/src',
-            build_dir='/path/to/build')
+            workspace=self.workspace,
+            host=self.host)
 
-        self.assertEqual(ninja_build.ninja_bin_path, '/path/to/build/ninja')
+        self.assertEqual(ninja_build.ninja_bin_path,
+                         os.path.join(
+                             self.workspace.build_dir('build', 'ninja'),
+                             'ninja'))
 
     def test_build(self):
-        ninja_build = Ninja(
+        ninja_build = Ninja.new_builder(
             args=self.args,
             toolchain=self.toolchain,
-            source_dir=self.workspace.source_dir('ninja'),
-            build_dir=self.workspace.build_dir('build', 'ninja'))
+            workspace=self.workspace,
+            host=self.host)
 
         ninja_build.build()
 
@@ -113,8 +119,7 @@ def test_build(self):
 + pushd {build_dir}
 + {expect_env}{python} configure.py --bootstrap
 + popd
-""".format(
-            source_dir=os.path.join(self.workspace.source_root, 'ninja'),
-            build_dir=os.path.join(self.workspace.build_root, 'ninja-build'),
-            expect_env=expect_env,
-            python=sys.executable))
+""".format(source_dir=self.workspace.source_dir('ninja'),
+           build_dir=self.workspace.build_dir('build', 'ninja'),
+           expect_env=expect_env,
+           python=sys.executable))