com.google.javascript.jscomp.deps.ModuleLoader Maven / Gradle / Ivy
/*
* Copyright 2016 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.base.Preconditions.checkNotNull;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Function;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
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 java.nio.file.Paths;
import java.util.Comparator;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;
import javax.annotation.Nullable;
/**
* Provides compile-time locate semantics for ES6 and CommonJS modules.
*
* @see "https://tc39.github.io/ecma262/#sec-module-semantics"
* @see "http://wiki.commonjs.org/wiki/Modules/1.1"
*/
public final class ModuleLoader {
public static final DiagnosticType MODULE_CONFLICT =
DiagnosticType.warning(
"JSC_MODULE_CONFLICT",
"File cannot be a combination of goog.provide, goog.module, and/or ES6 module: {0}");
/** According to the spec, the forward slash should be the delimiter on all platforms. */
public static final String MODULE_SLASH = ModuleNames.MODULE_SLASH;
/** The default module root, the current directory. */
public static final String DEFAULT_FILENAME_PREFIX = "." + MODULE_SLASH;
public static final String JSC_BROWSER_BLACKLISTED_MARKER = "$jscomp$browser$blacklisted";
public static final DiagnosticType LOAD_WARNING =
DiagnosticType.error("JSC_JS_MODULE_LOAD_WARNING", "Failed to load module \"{0}\"");
public static final DiagnosticType INVALID_MODULE_PATH =
DiagnosticType.error(
"JSC_INVALID_MODULE_PATH", "Invalid module path \"{0}\" for resolution mode \"{1}\"");
private ErrorHandler errorHandler;
/** Root URIs to match module roots against. */
private final ImmutableList moduleRootPaths;
/** The set of all known input module URIs (including trailing .js), after normalization. */
private final ImmutableSet modulePaths;
/** Used to canonicalize paths before resolution. */
private final PathResolver pathResolver;
private final PathEscaper pathEscaper;
private final ModuleResolver moduleResolver;
/**
* Creates an instance of the module loader which can be used to locate ES6 and CommonJS modules.
*
* @param moduleRoots path prefixes to strip from module paths
* @param inputs all inputs to the compilation process. Used to ensure that resolved paths
* references an valid input.
* @param factory creates a module resolver, which determines how module identifiers are resolved
* @param pathResolver determines how to sanitize paths before resolving
* @param pathEscaper determines if / how paths should be escaped
*/
public ModuleLoader(
@Nullable ErrorHandler errorHandler,
Iterable moduleRoots,
Iterable inputs,
ModuleResolverFactory factory,
PathResolver pathResolver,
PathEscaper pathEscaper) {
checkNotNull(moduleRoots);
checkNotNull(inputs);
checkNotNull(pathResolver);
checkNotNull(pathEscaper);
this.pathResolver = pathResolver;
this.pathEscaper = pathEscaper;
this.errorHandler = errorHandler == null ? new NoopErrorHandler() : errorHandler;
this.moduleRootPaths = createRootPaths(moduleRoots, pathResolver, pathEscaper);
this.modulePaths =
resolvePaths(
Iterables.transform(Iterables.transform(inputs, DependencyInfo::getName), pathResolver),
moduleRootPaths,
pathEscaper);
this.moduleResolver =
factory.create(this.modulePaths, this.moduleRootPaths, this.errorHandler, this.pathEscaper);
}
public ModuleLoader(
@Nullable ErrorHandler errorHandler,
Iterable moduleRoots,
Iterable inputs,
ModuleResolverFactory factory,
PathResolver pathResolver) {
this(errorHandler, moduleRoots, inputs, factory, pathResolver, PathEscaper.ESCAPE);
}
public ModuleLoader(
@Nullable ErrorHandler errorHandler,
Iterable moduleRoots,
Iterable inputs,
ModuleResolverFactory factory) {
this(errorHandler, moduleRoots, inputs, factory, PathResolver.RELATIVE, PathEscaper.ESCAPE);
}
@VisibleForTesting
public Map getPackageJsonMainEntries() {
return this.moduleResolver.getPackageJsonMainEntries();
}
/**
* A path to a module. Provides access to the module's closurized name
* and a way to resolve relative paths.
*/
public class ModulePath {
private final String path;
private ModulePath(String path) {
this.path = path;
}
@Override
public String toString() {
return path;
}
/**
* Determines if this path is the same as another path, ignoring any potential leading slashes
* on both.
*/
public boolean equalsIgnoreLeadingSlash(ModulePath other) {
return other != null && toModuleName().equals(other.toModuleName());
}
/**
* Turns a filename into a JS identifier that is used for moduleNames in
* rewritten code. Removes leading /, replaces / with $, removes trailing .js
* and replaces - with _. All moduleNames get a "module$" prefix.
*/
public String toModuleName() {
return ModuleNames.toModuleName(path);
}
/**
* Find a JS module {@code requireName}. See
* https://nodejs.org/api/modules.html#modules_all_together
*
* @return The normalized module URI, or {@code null} if not found.
*/
@Nullable
public ModulePath resolveJsModule(String moduleAddress) {
return resolveJsModule(moduleAddress, null, -1, -1);
}
/**
* Find a JS module {@code requireName}. See
* https://nodejs.org/api/modules.html#modules_all_together
*
* @return The normalized module URI, or {@code null} if not found.
*/
@Nullable
public ModulePath resolveJsModule(
String moduleAddress, String sourcename, int lineno, int colno) {
String loadAddress =
moduleResolver.resolveJsModule(this.path, moduleAddress, sourcename, lineno, colno);
if (loadAddress != null) {
return new ModulePath(loadAddress);
}
return null;
}
/**
* Treats the module address as a path and returns the name of that module. Does not verify that
* there is actually a JS file at the provided URI.
*
* Primarily used for per-file ES6 module transpilation
*/
public ModulePath resolveModuleAsPath(String moduleAddress) {
return new ModulePath(moduleResolver.resolveModuleAsPath(this.path, moduleAddress));
}
}
/** Resolves a path into a {@link ModulePath}. */
public ModulePath resolve(String path) {
return new ModulePath(normalize(pathEscaper.escape(pathResolver.apply(path)), moduleRootPaths));
}
/** Whether this is relative to the current file, or a top-level identifier. */
public static boolean isRelativeIdentifier(String name) {
return name.startsWith("." + MODULE_SLASH) || name.startsWith(".." + MODULE_SLASH);
}
/** Whether this is absolute to the compilation. */
public static boolean isAbsoluteIdentifier(String name) {
return name.startsWith(MODULE_SLASH);
}
/** Whether this is neither absolute or relative. */
public static boolean isAmbiguousIdentifier(String name) {
return !isAbsoluteIdentifier(name) && !isRelativeIdentifier(name);
}
/** Whether name is a path-based identifier (has a '/' character) */
public static boolean isPathIdentifier(String name) {
return name.contains(MODULE_SLASH);
}
/**
* Normalizes the given root paths, which are path prefixes to be removed from a module path when
* resolved.
*/
private static ImmutableList createRootPaths(
Iterable roots, PathResolver resolver, PathEscaper escaper) {
// Sort longest length to shortest so that paths are applied most specific to least.
Set builder =
new TreeSet<>(
Comparator.comparingInt(String::length)
.thenComparing(Comparator.naturalOrder())
.reversed());
for (String root : roots) {
String rootModuleName = escaper.escape(resolver.apply(root));
if (isAmbiguousIdentifier(rootModuleName)) {
rootModuleName = MODULE_SLASH + rootModuleName;
}
builder.add(rootModuleName);
}
return ImmutableList.copyOf(builder);
}
/**
* @param modulePaths List of modules. Modules can be relative to the compilation root or absolute
* file system paths (or even absolute paths from the compilation root).
* @param roots List of module roots which anchor absolute path references.
* @return List of normalized modules which always have a leading slash
*/
private static ImmutableSet resolvePaths(
Iterable modulePaths, Iterable roots, PathEscaper escaper) {
ImmutableSet.Builder resolved = ImmutableSet.builder();
Set knownPaths = new HashSet<>();
for (String name : modulePaths) {
String canonicalizedPath = escaper.escape(name);
if (!knownPaths.add(normalize(canonicalizedPath, roots))) {
// Having root paths "a" and "b" and source files "a/f.js" and "b/f.js" is ambiguous.
throw new IllegalArgumentException(
"Duplicate module path after resolving: " + name);
}
if (isAmbiguousIdentifier(canonicalizedPath)) {
canonicalizedPath = MODULE_SLASH + canonicalizedPath;
}
resolved.add(canonicalizedPath);
}
return resolved.build();
}
/** Normalizes the name and resolves it against the module roots. */
static String normalize(String path, Iterable moduleRootPaths) {
String normalizedPath = path;
if (isAmbiguousIdentifier(normalizedPath)) {
normalizedPath = MODULE_SLASH + normalizedPath;
}
// Find a moduleRoot that this URI is under. If none, use as is.
for (String moduleRoot : moduleRootPaths) {
if (normalizedPath.startsWith(moduleRoot)) {
// Make sure that e.g. path "foobar/test.js" is not matched by module "foo", by checking for
// a leading slash.
String trailing = normalizedPath.substring(moduleRoot.length());
if (trailing.startsWith(MODULE_SLASH)) {
return trailing.substring(MODULE_SLASH.length());
}
}
}
// Not underneath any of the roots.
return path;
}
public void setErrorHandler(ErrorHandler errorHandler) {
if (errorHandler == null) {
this.errorHandler = new NoopErrorHandler();
} else {
this.errorHandler = errorHandler;
}
this.moduleResolver.setErrorHandler(this.errorHandler);
}
public ErrorHandler getErrorHandler() {
return this.errorHandler;
}
/** Indicates whether to escape characters in paths. */
public enum PathEscaper {
/**
* Escapes characters in paths according to {@link ModuleNames#escapePath(String)} and then
* canonicalizes it.
*/
ESCAPE {
@Override
public String escape(String path) {
return ModuleNames.escapePath(path);
}
},
/**
* Does not escaped characters in paths, but does canonicalize it according to {@link
* ModuleNames#canonicalizePath(String)}.
*/
CANONICALIZE_ONLY {
@Override
public String escape(String path) {
return ModuleNames.canonicalizePath(path);
}
};
public abstract String escape(String path);
}
/** An enum indicating whether to absolutize paths. */
public enum PathResolver implements Function {
RELATIVE {
@Override
public String apply(String path) {
return path;
}
},
@GwtIncompatible("Paths.get, Path.toAbsolutePath")
ABSOLUTE {
@Override
public String apply(String path) {
return Paths.get(path).toAbsolutePath().toString();
}
};
}
/** An enum used to specify what algorithm to use to locate non path-based modules */
@FunctionalInterface
public interface ModuleResolverFactory {
ModuleResolver create(
ImmutableSet modulePaths,
ImmutableList moduleRootPaths,
ErrorHandler errorHandler,
PathEscaper pathEscaper);
}
/** A trivial module loader with no roots. */
public static final ModuleLoader EMPTY =
new ModuleLoader(
/** errorReporter= */ null,
ImmutableList.of(),
ImmutableList.of(),
BrowserModuleResolver.FACTORY);
/** Standard path base resolution algorithms that are accepted as a command line flag. */
public enum ResolutionMode {
/**
* Mimics the behavior of MS Edge.
*
* Modules must begin with a "." or "/" character.
* Modules must include the file extension
* MS Edge was the only browser to define a module resolution behavior at the time of this
* writing.
*/
BROWSER,
/**
* A limited superset of BROWSER that transforms some path prefixes.
*
* For example one could configure this so that "@root/" is replaced with
* "/my/path/to/project/" within import paths.
*/
BROWSER_WITH_TRANSFORMED_PREFIXES,
/**
* Uses the node module resolution algorithm.
*
* Modules which do not begin with a "." or "/" character are looked up from the appropriate
* node_modules folder. Includes the ability to require directories and JSON files. Exact match,
* then ".js", then ".json" file extensions are searched.
*/
NODE,
/**
* Uses a lookup map provided by webpack to locate modules from a numeric id used during import
*/
WEBPACK,
}
private static final class NoopErrorHandler implements ErrorHandler {
@Override
public void report(CheckLevel level, JSError error) {}
}
}