com.google.idea.blaze.base.lang.projectview.completion.ProjectViewKeywordCompletionContributor.java Source code

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Here is the source code for com.google.idea.blaze.base.lang.projectview.completion.ProjectViewKeywordCompletionContributor.java

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/*
 * Copyright 2016 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.idea.blaze.base.lang.projectview.completion;

import static com.intellij.patterns.PlatformPatterns.psiElement;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.ImmutableList;
import com.google.idea.blaze.base.lang.projectview.language.ProjectViewLanguage;
import com.google.idea.blaze.base.lang.projectview.lexer.ProjectViewTokenType;
import com.google.idea.blaze.base.projectview.section.ListSectionParser;
import com.google.idea.blaze.base.projectview.section.ScalarSectionParser;
import com.google.idea.blaze.base.projectview.section.SectionParser;
import com.google.idea.blaze.base.projectview.section.sections.Sections;
import com.intellij.codeInsight.completion.AutoCompletionContext;
import com.intellij.codeInsight.completion.AutoCompletionDecision;
import com.intellij.codeInsight.completion.CompletionContributor;
import com.intellij.codeInsight.completion.CompletionParameters;
import com.intellij.codeInsight.completion.CompletionProvider;
import com.intellij.codeInsight.completion.CompletionResultSet;
import com.intellij.codeInsight.completion.CompletionType;
import com.intellij.codeInsight.completion.InsertHandler;
import com.intellij.codeInsight.completion.InsertionContext;
import com.intellij.codeInsight.lookup.LookupElement;
import com.intellij.codeInsight.lookup.LookupElementBuilder;
import com.intellij.lang.ASTNode;
import com.intellij.openapi.editor.Document;
import com.intellij.openapi.editor.Editor;
import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiFile;
import com.intellij.util.ProcessingContext;
import java.util.List;
import org.jetbrains.annotations.Nullable;

/** Completes project view section names. */
public class ProjectViewKeywordCompletionContributor extends CompletionContributor {

    @Override
    public AutoCompletionDecision handleAutoCompletionPossibility(AutoCompletionContext context) {
        // auto-insert the obvious only case; else show other cases.
        final LookupElement[] items = context.getItems();
        if (items.length == 1) {
            return AutoCompletionDecision.insertItem(items[0]);
        }
        return AutoCompletionDecision.SHOW_LOOKUP;
    }

    public ProjectViewKeywordCompletionContributor() {
        extend(CompletionType.BASIC,
                psiElement().withLanguage(ProjectViewLanguage.INSTANCE)
                        .withElementType(ProjectViewTokenType.IDENTIFIERS)
                        .andOr(psiElement().afterLeaf("\n"), psiElement().afterLeaf(psiElement().isNull())),
                new CompletionProvider<CompletionParameters>() {
                    @Override
                    protected void addCompletions(CompletionParameters parameters, ProcessingContext context,
                            CompletionResultSet result) {
                        result.addAllElements(keywordLookups);
                    }
                });
    }

    private static final List<LookupElement> keywordLookups = getLookups();

    private static List<LookupElement> getLookups() {
        ImmutableList.Builder<LookupElement> list = ImmutableList.builder();
        for (SectionParser parser : Sections.getUndeprecatedParsers()) {
            if (handledSectionType(parser)) {
                list.add(forSectionParser(parser));
            }
        }
        return list.build();
    }

    @VisibleForTesting
    public static boolean handledSectionType(SectionParser parser) {
        return parser instanceof ListSectionParser || parser instanceof ScalarSectionParser;
    }

    private static LookupElement forSectionParser(SectionParser parser) {
        return LookupElementBuilder.create(parser.getName()).withInsertHandler(insertDivider(parser));
    }

    private static InsertHandler<LookupElement> insertDivider(SectionParser parser) {
        return (context, item) -> {
            Editor editor = context.getEditor();
            Document document = editor.getDocument();
            context.commitDocument();

            String nextTokenText = findNextTokenText(context);
            if (nextTokenText == null || nextTokenText.equals("\n")) {
                document.insertString(context.getTailOffset(), getDivider(parser));
                editor.getCaretModel().moveToOffset(context.getTailOffset());
            }
        };
    }

    private static String getDivider(SectionParser parser) {
        if (parser instanceof ListSectionParser) {
            return ":\n  ";
        }
        char div = ((ScalarSectionParser) parser).getDivider();
        return div == ' ' ? String.valueOf(div) : (div + " ");
    }

    @Nullable
    private static String findNextTokenText(final InsertionContext context) {
        final PsiFile file = context.getFile();
        PsiElement element = file.findElementAt(context.getTailOffset());
        while (element != null && element.getTextLength() == 0) {
            ASTNode next = element.getNode().getTreeNext();
            element = next != null ? next.getPsi() : null;
        }
        return element != null ? element.getText() : null;
    }
}