fbcode_builder: getdeps: add BuilderBase class

Summary:
a builder knows how to build and install a project.

Later diffs add concrete implementations of the BuilderBase

Reviewed By: simpkins

Differential Revision: D14691018

fbshipit-source-id: 89b14614b5160353cd7e59f27037afcdf6229eb7

build/fbcode_builder/getdeps/builder.py

@@ -0,0 +1,90 @@
+#!/usr/bin/env python
+# Copyright (c) 2019-present, Facebook, Inc.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree. An additional grant
+# of patent rights can be found in the PATENTS file in the same directory.
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import glob
+import os
+
+from .envfuncs import Env
+from .runcmd import run_cmd
+
+
+class BuilderBase(object):
+    def __init__(
+        self, build_opts, ctx, manifest, src_dir, build_dir, inst_dir, env=None
+    ):
+        self.env = Env()
+        if env:
+            self.env.update(env)
+
+        subdir = manifest.get("build", "subdir", ctx=ctx)
+        if subdir:
+            src_dir = os.path.join(src_dir, subdir)
+
+        self.ctx = ctx
+        self.src_dir = src_dir
+        self.build_dir = build_dir or src_dir
+        self.inst_dir = inst_dir
+        self.build_opts = build_opts
+        self.manifest = manifest
+
+    def _run_cmd(self, cmd, cwd=None, env=None):
+        if env:
+            e = self.env.copy()
+            e.update(env)
+            env = e
+        else:
+            env = self.env
+
+        if self.build_opts.is_windows():
+            # On Windows, the compiler is not available in the PATH by default
+            # so we need to run the vcvarsall script to populate the environment.
+            # We use a glob to find some version of this script as deployed with
+            # Visual Studio 2017.  This logic will need updating when we switch
+            # to a newer compiler.
+            vcvarsall = glob.glob(
+                os.path.join(
+                    os.environ["ProgramFiles(x86)"],
+                    "Microsoft Visual Studio",
+                    "2017",
+                    "*",
+                    "VC",
+                    "Auxiliary",
+                    "Build",
+                    "vcvarsall.bat",
+                )
+            )
+
+            if len(vcvarsall) > 0:
+                # Since it sets rather a large number of variables we mildly abuse
+                # the cmd quoting rules to assemble a command that calls the script
+                # to prep the environment and then triggers the actual command that
+                # we wanted to run.
+                cmd = [vcvarsall[0], "amd64", "&&"] + cmd
+
+        run_cmd(cmd=cmd, env=env, cwd=cwd or self.build_dir)
+
+    def build(self, install_dirs, reconfigure):
+        print("Building %s..." % self.manifest.name)
+
+        if self.build_dir is not None:
+            if not os.path.isdir(self.build_dir):
+                os.makedirs(self.build_dir)
+                reconfigure = True
+
+        self._build(install_dirs=install_dirs, reconfigure=reconfigure)
+
+    def _build(self, install_dirs, reconfigure):
+        """ Perform the build.
+        install_dirs contains the list of installation directories for
+        the dependencies of this project.
+        reconfigure will be set to true if the fetcher determined
+        that the sources have changed in such a way that the build
+        system needs to regenerate its rules. """
+        pass