Support finding packages in the JRT rather than just classpath (#10153)

Fixes #10149

Author: niloc132

dev/core/src/com/google/gwt/dev/javac/JdtCompiler.java

@@ -78,8 +78,12 @@
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
+import java.net.URI;
 import java.net.URISyntaxException;
 import java.net.URL;
+import java.nio.file.FileSystem;
+import java.nio.file.FileSystems;
+import java.nio.file.Files;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -384,13 +388,20 @@ private static class INameEnvironmentImpl implements INameEnvironment {
 
     private final Map<String, CompiledClass> internalTypes;
 
+    private final FileSystem jrt = FileSystems.getFileSystem(URI.create("jrt:/"));
+
     public INameEnvironmentImpl(Set<String> packages, Map<String, CompiledClass> internalTypes) {
       this.packages = packages;
       this.internalTypes = internalTypes;
     }
 
     @Override
     public void cleanup() {
+      try {
+        jrt.close();
+      } catch (IOException e) {
+        // Ignore failure to close read-only jrt file system
+      }
     }
 
     @Override
@@ -547,8 +558,8 @@ private NameEnvironmentAnswer doFindTypeInClassPath(String internalName) {
 
           ClassFileReader classFileReader =
               ClassFileReader.read(openStream, resource.toExternalForm(), true);
-          // In case insensitive file systems we might have found a resource  whose name is different
-          // in case and should not be returned as an answer.
+          // In case-insensitive file systems we might have found a resource whose name is
+          // different in case and should not be returned as an answer.
           if (internalName.equals(CharOperation.charToString(classFileReader.getName()))) {
             return new NameEnvironmentAnswer(classFileReader, null);
           }
@@ -606,14 +617,40 @@ private boolean isPackage(String slashedPackageName) {
         return false;
       }
       // Include class loader check for binary-only annotations.
-      if (caseSensitivePathExists(slashedPackageName)) {
+      if (caseSensitivePackageExists(slashedPackageName)) {
         addPackages(packages, slashedPackageName);
         return true;
       } else {
         notPackages.add(slashedPackageName);
         return false;
       }
     }
+
+    private boolean caseSensitivePackageExists(String slashedPackage) {
+      URL resourceURL = getClassLoader().getResource(slashedPackage + '/');
+      if (resourceURL == null) {
+        // Can't be found in jars or class directories - might be system defined, test jrt
+        String pkg = slashedPackage.replace('/', '.');
+        // This check is always case-sensitive - we're looking inside the modules, rather than on
+        // the host file system, so no additional checks are needed.
+        return Files.exists(jrt.getPath("/packages", pkg));
+      }
+
+      try {
+        File resourceFile = new File(resourceURL.toURI());
+        return Arrays.asList(resourceFile.getParentFile().list()).contains(resourceFile.getName());
+      } catch (URISyntaxException e) {
+        // The URL can not be converted to a URI.
+      } catch (IllegalArgumentException e) {
+        // A file instance can not be constructed from a URI.
+      }
+
+      // Some exception occurred while trying to make sure the name for the resource on disk is
+      // exactly the same as the one requested including case. If an exception is thrown in the
+      // process we assume that the URI does not refer to a resource in the filesystem and that the
+      // resource obtained from the classloader is the one requested.
+      return true;
+    }
   }
 
   /**
@@ -1091,28 +1128,6 @@ private static void addPackages(Set<String> packages, String slashedPackageName)
     }
   }
 
-  private static boolean caseSensitivePathExists(String resourcePath) {
-    URL resourceURL = getClassLoader().getResource(resourcePath + '/');
-    if (resourceURL == null) {
-      return false;
-    }
-
-    try {
-      File resourceFile = new File(resourceURL.toURI());
-      return Arrays.asList(resourceFile.getParentFile().list()).contains(resourceFile.getName());
-    } catch (URISyntaxException e) {
-      // The URL can not be converted to a URI.
-    } catch (IllegalArgumentException e) {
-      // A file instance can not be constructed from a URI.
-    }
-
-    // Some exception occurred while trying to make sure the name for the resource on disk is
-    // exactly the same as the one requested including case. If an exception is thrown in the
-    // process we assume that the URI does not refer to a resource in the filesystem and that the
-    // resource obtained from the classloader is the one requested.
-    return true;
-  }
-
   private static ClassLoader getClassLoader() {
     return Thread.currentThread().getContextClassLoader();
   }

dev/core/test/com/google/gwt/dev/javac/JdtCompilerTest.java

@@ -127,6 +127,19 @@ public void testSourceNames() throws Exception {
         "com.google.Outer.Inner", "com.google.Outer.Inner.Deep$est", "com.google.Pseudo$Inner")));
   }
 
+  public void testReferencesToJrtPackages() throws UnableToCompleteException {
+    // Pick two different annotations from different java modules, with no emulation in GWT,
+    // and confirm they can compile
+    assertUnitCompilesWithNoErrors("com.example.JrtPackageReference",
+        "package com.example;",
+        "import javax.annotation.processing.Generated;",
+        "import jdk.jfr.Label;",
+        "@Generated(\"foo\")",
+        "@Label(\"asdf\")",
+        "public class JrtPackageReference {",
+        "}");
+  }
+
   private void assertUnitCompilesWithNoErrors(String sourceName, String... sourceLines)
       throws UnableToCompleteException {
     CompilationUnit unit = compileUnit(sourceName, sourceLines);