[jnigen] Use .jar metadata to generate generic types (#158)

Closes #132.

ASM backend, parses classes, fields and method signatures from the metadata to add generic type information to other-wise type-erased generics.

Author: HosseinYousefi

pkgs/jnigen/example/in_app_java/jnigen.yaml

@@ -14,3 +14,4 @@ source_path:
 classes:
   - 'com.example.in_app_java.AndroidUtils' # from source_path
   - 'android.os.Build' # from gradle's compile classpath
+  - 'java.util.HashMap' # from gradle's compile classpath

pkgs/jnigen/example/in_app_java/lib/android_utils.dart

@@ -11,9 +11,24 @@ import 'android_utils.dart';
 
 JObject activity = JObject.fromRef(Jni.getCurrentActivity());
 
-/// Display device model number as Toast
+final hashmap = HashMap.ctor2(JString.type, JString.type);
+
+extension IntX on int {
+  JString toJString() {
+    return toString().toJString();
+  }
+}
+
+/// Display device model number and the number of times this was called
+/// as Toast.
 void showToast() {
-  AndroidUtils.showToast(activity, Build.MODEL, 0);
+  final toastCount =
+      hashmap.getOrDefault("toastCount".toJString(), 0.toJString());
+  final newToastCount = (int.parse(toastCount.toDartString()) + 1).toJString();
+  hashmap.put("toastCount".toJString(), newToastCount);
+  final message =
+      '${newToastCount.toDartString()} - ${Build.MODEL.toDartString()}';
+  AndroidUtils.showToast(activity, message.toJString(), 0);
 }
 
 void main() {

pkgs/jnigen/example/in_app_java/lib/main.dart

@@ -484,7 +484,7 @@ class PDDocument extends jni.JObject {
   ///@return a <code>List</code> of <code>PDSignatureField</code>s
   ///@throws IOException if no document catalog can be found.
   jni.JObject getSignatureFields() =>
-      jni.JObjectType().fromRef(_getSignatureFields(reference).object);
+      const jni.JObjectType().fromRef(_getSignatureFields(reference).object);
 
   static final _getSignatureDictionaries = jniLookup<
               ffi.NativeFunction<
@@ -498,8 +498,8 @@ class PDDocument extends jni.JObject {
   /// Retrieve all signature dictionaries from the document.
   ///@return a <code>List</code> of <code>PDSignatureField</code>s
   ///@throws IOException if no document catalog can be found.
-  jni.JObject getSignatureDictionaries() =>
-      jni.JObjectType().fromRef(_getSignatureDictionaries(reference).object);
+  jni.JObject getSignatureDictionaries() => const jni.JObjectType()
+      .fromRef(_getSignatureDictionaries(reference).object);
 
   static final _registerTrueTypeFontForClosing = jniLookup<
               ffi.NativeFunction<

pkgs/jnigen/example/in_app_java/src/android_utils/android_utils.c

@@ -377,7 +377,7 @@ class PDDocumentInformation extends jni.JObject {
   ///@return all metadata key strings.
   ///@since Apache PDFBox 1.3.0
   jni.JObject getMetadataKeys() =>
-      jni.JObjectType().fromRef(_getMetadataKeys(reference).object);
+      const jni.JObjectType().fromRef(_getMetadataKeys(reference).object);
 
   static final _getCustomMetadataValue = jniLookup<
               ffi.NativeFunction<

pkgs/jnigen/example/pdfbox_plugin/lib/src/third_party/org/apache/pdfbox/pdmodel/PDDocument.dart

@@ -100,8 +100,8 @@ class PDFTextStripper extends jni.JObject {
   /// text after second article
   ///
   /// Most PDFs won't have any beads, so charactersByArticle will contain a single entry.
-  jni.JObject get charactersByArticle =>
-      jni.JObjectType().fromRef(_get_charactersByArticle(reference).object);
+  jni.JObject get charactersByArticle => const jni.JObjectType()
+      .fromRef(_get_charactersByArticle(reference).object);
   static final _set_charactersByArticle = jniLookup<
               ffi.NativeFunction<
                   jni.JThrowablePtr Function(
@@ -642,8 +642,8 @@ class PDFTextStripper extends jni.JObject {
   /// Character strings are grouped by articles. It is quite common that there will only be a single article. This
   /// returns a List that contains List objects, the inner lists will contain TextPosition objects.
   ///@return A double List of TextPositions for all text strings on the page.
-  jni.JObject getCharactersByArticle() =>
-      jni.JObjectType().fromRef(_getCharactersByArticle(reference).object);
+  jni.JObject getCharactersByArticle() => const jni.JObjectType()
+      .fromRef(_getCharactersByArticle(reference).object);
 
   static final _setSuppressDuplicateOverlappingText = jniLookup<
               ffi.NativeFunction<
@@ -1191,7 +1191,7 @@ class PDFTextStripper extends jni.JObject {
   /// This method returns a list of such regular expression Patterns.
   ///@return a list of Pattern objects.
   jni.JObject getListItemPatterns() =>
-      jni.JObjectType().fromRef(_getListItemPatterns(reference).object);
+      const jni.JObjectType().fromRef(_getListItemPatterns(reference).object);
 
   static final _matchPattern = jniLookup<
           ffi.NativeFunction<

pkgs/jnigen/example/pdfbox_plugin/lib/src/third_party/org/apache/pdfbox/pdmodel/PDDocumentInformation.dart

@@ -0,0 +1,54 @@
+// Copyright (c) 2022, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+package com.github.dart_lang.jnigen.apisummarizer.disasm;
+
+import com.github.dart_lang.jnigen.apisummarizer.elements.ClassDecl;
+import com.github.dart_lang.jnigen.apisummarizer.elements.TypeParam;
+import com.github.dart_lang.jnigen.apisummarizer.elements.TypeUsage;
+import org.objectweb.asm.signature.SignatureVisitor;
+
+public class AsmClassSignatureVisitor extends SignatureVisitor {
+  private final ClassDecl decl;
+  private int interfaceIndex = -1;
+
+  public AsmClassSignatureVisitor(ClassDecl decl) {
+    super(AsmConstants.API);
+    this.decl = decl;
+  }
+
+  @Override
+  public void visitFormalTypeParameter(String name) {
+    var typeParam = new TypeParam();
+    typeParam.name = name;
+    decl.typeParams.add(typeParam);
+  }
+
+  @Override
+  public SignatureVisitor visitClassBound() {
+    var typeUsage = new TypeUsage();
+    // ClassDecl initially has no type parameters. In visitFormalTypeParameter we add them
+    // and sequentially visitClassBound and visitInterfaceBound.
+    decl.typeParams.get(decl.typeParams.size() - 1).bounds.add(typeUsage);
+    return new AsmTypeUsageSignatureVisitor(typeUsage);
+  }
+
+  @Override
+  public SignatureVisitor visitInterfaceBound() {
+    var typeUsage = new TypeUsage();
+    decl.typeParams.get(decl.typeParams.size() - 1).bounds.add(typeUsage);
+    return new AsmTypeUsageSignatureVisitor(typeUsage);
+  }
+
+  @Override
+  public SignatureVisitor visitSuperclass() {
+    return new AsmTypeUsageSignatureVisitor(decl.superclass);
+  }
+
+  @Override
+  public SignatureVisitor visitInterface() {
+    interfaceIndex++;
+    return new AsmTypeUsageSignatureVisitor(decl.interfaces.get(interfaceIndex));
+  }
+}

pkgs/jnigen/example/pdfbox_plugin/lib/src/third_party/org/apache/pdfbox/text/PDFTextStripper.dart

@@ -12,6 +12,7 @@
 import com.github.dart_lang.jnigen.apisummarizer.util.StreamUtil;
 import java.util.*;
 import org.objectweb.asm.*;
+import org.objectweb.asm.signature.SignatureReader;
 
 public class AsmClassVisitor extends ClassVisitor implements AsmAnnotatedElementVisitor {
   private static Param param(
@@ -53,6 +54,10 @@ public void visit(
     current.superclass = TypeUtils.typeUsage(Type.getObjectType(superName), null);
     current.interfaces =
         StreamUtil.map(interfaces, i -> TypeUtils.typeUsage(Type.getObjectType(i), null));
+    if (signature != null) {
+      var reader = new SignatureReader(signature);
+      reader.accept(new AsmClassSignatureVisitor(current));
+    }
     super.visit(version, access, name, signature, superName, interfaces);
   }
 
@@ -66,11 +71,16 @@ public FieldVisitor visitField(
     if (name.contains("$")) {
       return null;
     }
+
     var field = new Field();
     field.name = name;
     field.type = TypeUtils.typeUsage(Type.getType(descriptor), signature);
     field.defaultValue = value;
     field.modifiers = TypeUtils.access(access);
+    if (signature != null) {
+      var reader = new SignatureReader(signature);
+      reader.accept(new AsmTypeUsageSignatureVisitor(field.type));
+    }
     peekVisiting().fields.add(field);
     return new AsmFieldVisitor(field);
   }
@@ -101,6 +111,10 @@ public MethodVisitor visitMethod(
     method.returnType = TypeUtils.typeUsage(type.getReturnType(), signature);
     method.modifiers = TypeUtils.access(access);
     method.params = params;
+    if (signature != null) {
+      var reader = new SignatureReader(signature);
+      reader.accept(new AsmMethodSignatureVisitor(method));
+    }
     peekVisiting().methods.add(method);
     return new AsmMethodVisitor(method);
   }

pkgs/jnigen/java/src/main/java/com/github/dart_lang/jnigen/apisummarizer/disasm/AsmClassSignatureVisitor.java

@@ -0,0 +1,60 @@
+// Copyright (c) 2022, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+package com.github.dart_lang.jnigen.apisummarizer.disasm;
+
+import com.github.dart_lang.jnigen.apisummarizer.elements.Method;
+import com.github.dart_lang.jnigen.apisummarizer.elements.TypeParam;
+import com.github.dart_lang.jnigen.apisummarizer.elements.TypeUsage;
+import org.objectweb.asm.signature.SignatureVisitor;
+
+public class AsmMethodSignatureVisitor extends SignatureVisitor {
+  private final Method method;
+  private int paramIndex = -1;
+
+  public AsmMethodSignatureVisitor(Method method) {
+    super(AsmConstants.API);
+    this.method = method;
+  }
+
+  @Override
+  public void visitFormalTypeParameter(String name) {
+    var typeParam = new TypeParam();
+    typeParam.name = name;
+    method.typeParams.add(typeParam);
+  }
+
+  @Override
+  public SignatureVisitor visitClassBound() {
+    var typeUsage = new TypeUsage();
+    // Method initially has no type parameters. In visitFormalTypeParameter we add them
+    // and sequentially visitClassBound and visitInterfaceBound.
+    method.typeParams.get(method.typeParams.size() - 1).bounds.add(typeUsage);
+    return new AsmTypeUsageSignatureVisitor(typeUsage);
+  }
+
+  @Override
+  public SignatureVisitor visitInterfaceBound() {
+    var typeUsage = new TypeUsage();
+    method.typeParams.get(method.typeParams.size() - 1).bounds.add(typeUsage);
+    return new AsmTypeUsageSignatureVisitor(typeUsage);
+  }
+
+  @Override
+  public SignatureVisitor visitReturnType() {
+    return new AsmTypeUsageSignatureVisitor(method.returnType);
+  }
+
+  @Override
+  public SignatureVisitor visitParameterType() {
+    paramIndex++;
+    return new AsmTypeUsageSignatureVisitor(method.params.get(paramIndex).type);
+  }
+
+  @Override
+  public SignatureVisitor visitExceptionType() {
+    // Do nothing.
+    return new AsmTypeUsageSignatureVisitor(new TypeUsage());
+  }
+}

pkgs/jnigen/java/src/main/java/com/github/dart_lang/jnigen/apisummarizer/disasm/AsmClassVisitor.java

@@ -0,0 +1,99 @@
+// Copyright (c) 2022, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+package com.github.dart_lang.jnigen.apisummarizer.disasm;
+
+import com.github.dart_lang.jnigen.apisummarizer.elements.TypeUsage;
+import java.util.ArrayList;
+import org.objectweb.asm.signature.SignatureVisitor;
+
+public class AsmTypeUsageSignatureVisitor extends SignatureVisitor {
+  private final TypeUsage typeUsage;
+
+  public AsmTypeUsageSignatureVisitor(TypeUsage typeUsage) {
+    super(AsmConstants.API);
+    this.typeUsage = typeUsage;
+  }
+
+  @Override
+  public void visitBaseType(char descriptor) {
+    typeUsage.kind = TypeUsage.Kind.PRIMITIVE;
+    var name = "";
+    switch (descriptor) {
+      case 'Z':
+        name = "boolean";
+        break;
+      case 'B':
+        name = "byte";
+        break;
+      case 'C':
+        name = "char";
+        break;
+      case 'D':
+        name = "double";
+        break;
+      case 'F':
+        name = "float";
+        break;
+      case 'I':
+        name = "int";
+        break;
+      case 'J':
+        name = "long";
+        break;
+      case 'L':
+        name = "object";
+        break;
+      case 'S':
+        name = "short";
+        break;
+      case 'V':
+        name = "void";
+        break;
+    }
+    typeUsage.shorthand = name;
+    typeUsage.type = new TypeUsage.PrimitiveType(name);
+  }
+
+  @Override
+  public SignatureVisitor visitArrayType() {
+    typeUsage.kind = TypeUsage.Kind.ARRAY;
+    typeUsage.shorthand = "java.lang.Object[]";
+    var elementType = new TypeUsage();
+    typeUsage.type = new TypeUsage.Array(elementType);
+    return new AsmTypeUsageSignatureVisitor(elementType);
+  }
+
+  @Override
+  public void visitTypeVariable(String name) {
+    typeUsage.kind = TypeUsage.Kind.TYPE_VARIABLE;
+    typeUsage.shorthand = name;
+    typeUsage.type = new TypeUsage.TypeVar(name);
+  }
+
+  @Override
+  public void visitClassType(String name) {
+    typeUsage.kind = TypeUsage.Kind.DECLARED;
+    typeUsage.shorthand = name.substring(0, name.length()).replace('/', '.');
+    var components = name.split("[/$]");
+    var simpleName = components[components.length - 1];
+    typeUsage.type = new TypeUsage.DeclaredType(name, simpleName, new ArrayList<>());
+  }
+
+  @Override
+  public SignatureVisitor visitTypeArgument(char wildcard) {
+    // TODO(#141) support wildcards
+    // TODO(#144) support extend/super clauses
+    assert (typeUsage.type instanceof TypeUsage.DeclaredType);
+    var typeArg = new TypeUsage();
+    ((TypeUsage.DeclaredType) typeUsage.type).params.add(typeArg);
+    return new AsmTypeUsageSignatureVisitor(typeArg);
+  }
+
+  @Override
+  public void visitInnerClassType(String name) {
+    super.visitInnerClassType(name);
+    // TODO(#139) support nested generic classes
+  }
+}

pkgs/jnigen/java/src/main/java/com/github/dart_lang/jnigen/apisummarizer/disasm/AsmMethodSignatureVisitor.java

@@ -32,11 +32,11 @@ public class ClassDecl {
 
   public String parentName;
   public String packageName;
-  public List<TypeParam> typeParams;
+  public List<TypeParam> typeParams = new ArrayList<>();
   public List<Method> methods = new ArrayList<>();
   public List<Field> fields = new ArrayList<>();
   public TypeUsage superclass;
-  public List<TypeUsage> interfaces;
+  public List<TypeUsage> interfaces = new ArrayList<>();
   public boolean hasStaticInit;
   public boolean hasInstanceInit;
   public JavaDocComment javadoc;

pkgs/jnigen/java/src/main/java/com/github/dart_lang/jnigen/apisummarizer/disasm/AsmTypeUsageSignatureVisitor.java

@@ -12,7 +12,7 @@
 public class Method {
   public Set<String> modifiers = new HashSet<>();
   public String name;
-  public List<TypeParam> typeParams;
+  public List<TypeParam> typeParams = new ArrayList<>();
   public List<Param> params = new ArrayList<>();
   public TypeUsage returnType;
 

pkgs/jnigen/java/src/main/java/com/github/dart_lang/jnigen/apisummarizer/elements/ClassDecl.java

@@ -4,9 +4,10 @@
 
 package com.github.dart_lang.jnigen.apisummarizer.elements;
 
+import java.util.ArrayList;
 import java.util.List;
 
 public class TypeParam {
   public String name;
-  public List<TypeUsage> bounds;
+  public List<TypeUsage> bounds = new ArrayList<>();
 }