bind-gen: Implement PathManager

PathManager provides paths to Blink headers and output files.
Also supports cross-components output.

Bug: 839389
Change-Id: If9514f421ac8dd2d54c68cd9048a5ad5d1eb0536
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1897577
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712460}

third_party/blink/renderer/bindings/scripts/bind_gen/path_manager.py

+# Copyright 2019 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import os.path
+
+from . import name_style
+
+
+class PathManager(object):
+    """
+    Provides a variety of paths such as Blink headers and output files.
+
+    About output files, there are two cases.
+    - cross-components case:
+        APIs are generated in 'core' and implementations are generated in
+        'modules'.
+    - single component case:
+        Everything is generated in a single component.
+    """
+
+    def __init__(self, idl_definition, output_dirs):
+        idl_path = idl_definition.debug_info.location.filepath
+        self._idl_basepath, _ = os.path.splitext(idl_path)
+        self._idl_dir, self._idl_basename = os.path.split(self._idl_basepath)
+
+        components = idl_definition.components
+        assert 0 < len(components)
+
+        if len(components) == 1:
+            component = components[0]
+            self._is_cross_components = False
+            self._api_component = component
+            self._impl_component = component
+        else:
+            assert ("core", "modules") == sorted(components)
+            self._is_cross_components = True
+            self._api_component = "core"
+            self._impl_component = "modules"
+
+        self._api_dir = output_dirs[self._api_component]
+        self._impl_dir = output_dirs[self._impl_component]
+
+        self._out_basename = name_style.file("v8", idl_definition.identifier)
+
+    @property
+    def idl_dir(self):
+        return self._idl_dir
+
+    def blink_path(self, filename=None, ext=None):
+        # The IDL file and Blink headers are supposed to exist in the same
+        # directory.
+        return self._join(
+            dirpath=self.idl_dir,
+            filename=(filename or self._idl_basename),
+            ext=ext)
+
+    @property
+    def is_cross_components(self):
+        return self._is_cross_components
+
+    @property
+    def api_component(self):
+        return self._api_component
+
+    @property
+    def api_dir(self):
+        return self._api_dir
+
+    def api_path(self, filename=None, ext=None):
+        return self._join(
+            dirpath=self.api_dir,
+            filename=(filename or self._out_basename),
+            ext=ext)
+
+    @property
+    def impl_component(self):
+        return self._impl_component
+
+    @property
+    def impl_dir(self):
+        return self._impl_dir
+
+    def impl_path(self, filename=None, ext=None):
+        return self._join(
+            dirpath=self.impl_dir,
+            filename=(filename or self._out_basename),
+            ext=ext)
+
+    def _join(self, dirpath, filename, ext=None):
+        if ext is not None:
+            filename = "{}.{}".format(filename, ext)
+        return os.path.join(dirpath, filename)