com.google.devtools.build.docgen.BlazeRuleHelpPrinter.java Source code

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Here is the source code for com.google.devtools.build.docgen.BlazeRuleHelpPrinter.java

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// Copyright 2014 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.devtools.build.docgen;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.devtools.build.lib.analysis.ConfiguredRuleClassProvider;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

/**
 * A helper class to load and store printable build rule documentation. The doc
 * printed here doesn't contain attribute and implicit output definitions, just
 * the general rule documentation and examples.
 */
public class BlazeRuleHelpPrinter {

    private static Map<String, RuleDocumentation> ruleDocMap = null;

    /**
     * Returns the documentation of the given rule to be printed on the console.
     */
    public static String getRuleDoc(String ruleName, ConfiguredRuleClassProvider provider) {
        if (ruleDocMap == null) {
            try {
                BuildDocCollector collector = new BuildDocCollector(provider, false);
                Map<String, RuleDocumentation> ruleDocs = collector.collect(ImmutableList
                        .of("java/com/google/devtools/build/lib/view", "java/com/google/devtools/build/lib/rules"),
                        null);
                ruleDocMap = new HashMap<>();
                for (RuleDocumentation ruleDoc : ruleDocs.values()) {
                    ruleDocMap.put(ruleDoc.getRuleName(), ruleDoc);
                }
            } catch (BuildEncyclopediaDocException e) {
                return e.getErrorMsg();
            } catch (IOException e) {
                return e.getMessage();
            }
        }
        // Every rule should be documented and this method should be called only
        // for existing rules (a check is performed in HelpCommand).
        Preconditions.checkState(ruleDocMap.containsKey(ruleName),
                String.format("ERROR: Documentation of rule %s does not exist.", ruleName));
        return "Rule " + ruleName + ":" + ruleDocMap.get(ruleName).getCommandLineDocumentation() + "\n";
    }
}