com.google.javascript.jscomp.deps.BrowserWithTransformedPrefixesModuleResolver.java Source code

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Here is the source code for com.google.javascript.jscomp.deps.BrowserWithTransformedPrefixesModuleResolver.java

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/*
 * Copyright 2017 The Closure Compiler Authors.
 *
 * 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.javascript.jscomp.deps;

import static com.google.common.collect.ImmutableSortedSet.toImmutableSortedSet;

import com.google.auto.value.AutoValue;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.javascript.jscomp.CheckLevel;
import com.google.javascript.jscomp.DiagnosticType;
import com.google.javascript.jscomp.ErrorHandler;
import com.google.javascript.jscomp.JSError;
import com.google.javascript.jscomp.deps.ModuleLoader.ModuleResolverFactory;
import com.google.javascript.jscomp.deps.ModuleLoader.PathEscaper;
import java.util.Comparator;
import java.util.Set;
import java.util.stream.Collectors;
import javax.annotation.Nullable;

/**
 * Limited superset of the {@link BrowserModuleResolver} that allows for replacing some path
 * prefixes before resolving.
 */
public class BrowserWithTransformedPrefixesModuleResolver extends ModuleResolver {

    static final DiagnosticType INVALID_AMBIGUOUS_PATH = DiagnosticType.error("JSC_INVALID_AMBIGUOUS_PATH",
            "The path \"{0}\" is invalid. Expected any of the following prefixes for non-relative "
                    + "paths: {1}.");

    /** Factory for {@link BrowserWithTransformedPrefixesModuleResolver}. */
    public static final class Factory implements ModuleResolverFactory {
        private final ImmutableMap<String, String> prefixReplacements;

        public Factory(ImmutableMap<String, String> prefixReplacements) {
            this.prefixReplacements = prefixReplacements;
        }

        @Override
        public ModuleResolver create(ImmutableSet<String> modulePaths, ImmutableList<String> moduleRootPaths,
                ErrorHandler errorHandler, PathEscaper pathEscaper) {
            return new BrowserWithTransformedPrefixesModuleResolver(modulePaths, moduleRootPaths, errorHandler,
                    pathEscaper, prefixReplacements);
        }
    }

    /**
     * Struct of prefix and replacement. Has a natural ordering from longest prefix to shortest
     * prefix.
     */
    @AutoValue
    abstract static class PrefixReplacement {
        abstract String prefix();

        abstract String replacement();

        public static PrefixReplacement of(String prefix, String replacement) {
            return new AutoValue_BrowserWithTransformedPrefixesModuleResolver_PrefixReplacement(prefix,
                    replacement);
        }
    }

    private final ImmutableSet<PrefixReplacement> prefixReplacements;
    private final String expectedPrefixes;

    public BrowserWithTransformedPrefixesModuleResolver(ImmutableSet<String> modulePaths,
            ImmutableList<String> moduleRootPaths, ErrorHandler errorHandler, PathEscaper pathEscaper,
            ImmutableMap<String, String> prefixReplacements) {
        super(modulePaths, moduleRootPaths, errorHandler, pathEscaper);
        Set<PrefixReplacement> p = prefixReplacements.entrySet().stream()
                .map(entry -> PrefixReplacement.of(entry.getKey(), entry.getValue())).collect(toImmutableSortedSet(
                        // Sort by length in descending order to prefixes are applied most specific to
                        // least specific.
                        Comparator.<PrefixReplacement>comparingInt(r -> r.prefix().length()).reversed()
                                .thenComparing(PrefixReplacement::prefix)));
        this.prefixReplacements = ImmutableSet.copyOf(p);
        this.expectedPrefixes = this.prefixReplacements.stream().map(PrefixReplacement::prefix).sorted()
                .collect(Collectors.joining(", "));
    }

    @Nullable
    @Override
    public String resolveJsModule(String scriptAddress, String moduleAddress, String sourcename, int lineno,
            int colno) {
        String transformedAddress = moduleAddress;

        boolean replaced = false;

        for (PrefixReplacement prefixReplacement : prefixReplacements) {
            if (moduleAddress.startsWith(prefixReplacement.prefix())) {
                transformedAddress = prefixReplacement.replacement()
                        + moduleAddress.substring(prefixReplacement.prefix().length());
                replaced = true;
                break;
            }
        }

        // If ambiguous after the loop it was not transformed and the original moduleAddress is
        // ambiguous with an unrecognized prefix. Allow transformed paths to be ambiguous after
        // transformation to maybe match how files are passed to the compiler.
        if (!replaced && ModuleLoader.isAmbiguousIdentifier(transformedAddress)) {
            errorHandler.report(CheckLevel.WARNING, JSError.make(sourcename, lineno, colno, INVALID_AMBIGUOUS_PATH,
                    transformedAddress, expectedPrefixes));
            return null;
        }

        String loadAddress = locate(scriptAddress, transformedAddress);
        if (transformedAddress == null) {
            errorHandler.report(CheckLevel.WARNING,
                    JSError.make(sourcename, lineno, colno, ModuleLoader.LOAD_WARNING, moduleAddress));
        }
        return loadAddress;
    }

    @Override
    public String resolveModuleAsPath(String scriptAddress, String moduleAddress) {
        if (ModuleLoader.isRelativeIdentifier(moduleAddress)) {
            return super.resolveModuleAsPath(scriptAddress, moduleAddress);
        }

        String transformedAddress = moduleAddress;
        for (PrefixReplacement prefixReplacement : prefixReplacements) {
            if (moduleAddress.startsWith(prefixReplacement.prefix())) {
                transformedAddress = prefixReplacement.replacement()
                        + moduleAddress.substring(prefixReplacement.prefix().length());
                break;
            }
        }

        return ModuleLoader.normalize(transformedAddress, moduleRootPaths);
    }
}