50 lines
1.7 KiB
Python
50 lines
1.7 KiB
Python
# Copyright 2022 The Bazel Authors. All rights reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""A rule that performs template expansion.
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"""
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def _expand_template_impl(ctx):
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ctx.actions.expand_template(
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template = ctx.file.template,
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output = ctx.outputs.out,
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substitutions = ctx.attr.substitutions,
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)
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expand_template = rule(
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implementation = _expand_template_impl,
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doc = """Template expansion
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This performs a simple search over the template file for the keys in
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substitutions, and replaces them with the corresponding values.
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There is no special syntax for the keys. To avoid conflicts, you would need to
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explicitly add delimiters to the key strings, for example "{KEY}" or "@KEY@".""",
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attrs = {
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"template": attr.label(
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mandatory = True,
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allow_single_file = True,
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doc = "The template file to expand.",
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),
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"substitutions": attr.string_dict(
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mandatory = True,
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doc = "A dictionary mapping strings to their substitutions.",
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),
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"out": attr.output(
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mandatory = True,
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doc = "The destination of the expanded file.",
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),
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},
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)
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