Codegen: JavaGenerator [7] - produce complete NativeModule spec .java…

… files

Summary:
This implements the full NativeModuleResolvedType for each NativeModule spec, producing .java spec files in the output directory. The output files are now compiled during build time for :ReactAndroid and :packages:rn-tester:android:app.

Changelog: [Internal]

Reviewed By: mdvacca

Differential Revision: D23312858

fbshipit-source-id: c521b9d6602677fd275891cf44329740c6bd7387

packages/react-native-codegen/android/gradlePlugin-build/gradlePlugin/src/main/java/com/facebook/react/codegen/generator/JavaGenerator.java

@@ -7,6 +7,9 @@
 
 package com.facebook.react.codegen.generator;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import com.facebook.react.codegen.generator.model.CodegenException;
 import com.facebook.react.codegen.generator.model.TypeData;
 import com.facebook.react.codegen.generator.resolver.ResolvedType;
 import com.facebook.react.codegen.generator.resolver.TypeResolver;
@@ -15,9 +18,32 @@
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.stream.Collectors;
 
-// TODO: Implement proper generator - this is a sample usage of JavaPoet
+/**
+ * Given a react-native-codegen JSON schema, generate a set of .java files for React Native. The
+ * generator is isolated to a single schema, and a single Java package output.
+ */
 public final class JavaGenerator {
+  public static String LICENSE_HEADER =
+      "/*\n"
+          + " * Copyright (c) Facebook, Inc. and its affiliates.\n"
+          + " *\n"
+          + " * This source code is licensed under the MIT license found in the\n"
+          + " * LICENSE file in the root directory of this source tree.\n"
+          + " *\n"
+          + " * Generated by react-native-codegen JavaGenerator.\n"
+          + " *\n"
+          + " * @"
+          + "generated\n"
+          + " * @"
+          + "nolint\n"
+          + " */\n\n";
   private final File mSchemaFile;
   private final String mJavaPackageName;
   private final File mOutputDir;
@@ -28,24 +54,53 @@ public JavaGenerator(final File schemaFile, final String javaPackageName, final
     mOutputDir = outputDir;
   }
 
-  public void build() throws FileNotFoundException, IOException {
-    TypeData typeData = SchemaJsonParser.parse(mSchemaFile);
-    typeData
-        .getAllTypes()
-        .forEach(
-            t -> {
-              ResolvedType resolvedType =
-                  TypeResolver.resolveType(typeData.getType(t), typeData, false);
-              TypeSpec spec = resolvedType.getGeneratedCode(mJavaPackageName);
-              if (spec != null) {
-                final JavaFile javaFile = JavaFile.builder(mJavaPackageName, spec).build();
-                System.out.println(javaFile.toString());
-                try {
-                  javaFile.writeTo(mOutputDir);
-                } catch (IOException ex) {
-                  // TODO: Handle this in a different way.
-                }
-              }
-            });
+  public void build() throws CodegenException, FileNotFoundException, IOException {
+    // Step 1: Given a schema JSON, collect all types.
+    final TypeData typeData = SchemaJsonParser.parse(mSchemaFile);
+
+    // Step 2: Resolve each type, then collect those that produce a class or interface (TypeSpec).
+    final List<TypeSpec> typeSpecsToWrite =
+        typeData.getAllTypes().stream()
+            .map(
+                t -> {
+                  final ResolvedType resolvedType =
+                      TypeResolver.resolveType(typeData.getType(t), typeData, false);
+                  final TypeSpec spec = resolvedType.getGeneratedCode(mJavaPackageName);
+                  return spec;
+                })
+            .filter(f -> f != null)
+            .collect(Collectors.toList());
+
+    // Step 3: Write all of the TypeSpec's into the output directory.
+    for (final TypeSpec typeSpec : typeSpecsToWrite) {
+      writeTypeSpecToFile(typeSpec);
+    }
+  }
+
+  private final void writeTypeSpecToFile(final TypeSpec typeSpec)
+      throws CodegenException, IOException {
+    JavaFile file = JavaFile.builder(mJavaPackageName, typeSpec).skipJavaLangImports(true).build();
+
+    // Instead of using JavaFile.writeTo() API, manage the output files ourselves because
+    // JavaFile.addFileComment() does not support "block comment" style.
+    // See https://github.com/square/javapoet/issues/682#issuecomment-512238075.
+    Path outputDirPath = mOutputDir.toPath();
+
+    if (Files.exists(outputDirPath) && !Files.isDirectory(outputDirPath)) {
+      throw new CodegenException(
+          "Output path " + outputDirPath + " exists but is not a directory.");
+    }
+
+    if (!mJavaPackageName.isEmpty()) {
+      for (String packageComponent : mJavaPackageName.split("\\.")) {
+        outputDirPath = outputDirPath.resolve(packageComponent);
+      }
+      Files.createDirectories(outputDirPath);
+    }
+
+    Path outputPath = outputDirPath.resolve(typeSpec.name + ".java");
+    try (Writer writer = new OutputStreamWriter(Files.newOutputStream(outputPath), UTF_8)) {
+      writer.write(LICENSE_HEADER + file.toString());
+    }
   }
 }

packages/react-native-codegen/android/gradlePlugin-build/gradlePlugin/src/main/java/com/facebook/react/codegen/generator/resolver/Annotations.java

@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.react.codegen.generator.resolver;
+
+import com.squareup.javapoet.AnnotationSpec;
+import javax.annotation.Nullable;
+
+public class Annotations {
+  public static final AnnotationSpec OVERRIDE = AnnotationSpec.builder(Override.class).build();
+  public static final AnnotationSpec NULLABLE = AnnotationSpec.builder(Nullable.class).build();
+}

packages/react-native-codegen/android/gradlePlugin-build/gradlePlugin/src/main/java/com/facebook/react/codegen/generator/resolver/ClassNames.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.react.codegen.generator.resolver;
+
+import com.squareup.javapoet.ClassName;
+import com.squareup.javapoet.ParameterizedTypeName;
+import com.squareup.javapoet.TypeName;
+import java.util.Map;
+
+/** Names of Java classes required by generated code. */
+public class ClassNames {
+
+  // Java standard classes
+  public static final TypeName STRING = ClassName.get(String.class);
+
+  public static final ParameterizedTypeName CONSTANTS_MAP =
+      ParameterizedTypeName.get(ClassName.get(Map.class), ClassNames.STRING, ClassName.OBJECT);
+}

packages/react-native-codegen/android/gradlePlugin-build/gradlePlugin/src/main/java/com/facebook/react/codegen/generator/resolver/FunctionResolvedType.java

@@ -9,10 +9,16 @@
 
 import com.facebook.react.codegen.generator.model.FunctionType;
 import com.facebook.react.codegen.generator.model.TypeData;
+import com.squareup.javapoet.AnnotationSpec;
+import com.squareup.javapoet.CodeBlock;
+import com.squareup.javapoet.MethodSpec;
+import com.squareup.javapoet.ParameterSpec;
 import com.squareup.javapoet.TypeName;
 import java.util.Collections;
 import java.util.Map;
 import java.util.stream.Collectors;
+import javax.annotation.Nullable;
+import javax.lang.model.element.Modifier;
 
 public final class FunctionResolvedType extends ResolvedType<FunctionType> {
   private final Map<String, ResolvedType> mResolvedArgTypes;
@@ -47,4 +53,70 @@ public Map<String, ResolvedType> getResolvedArgTypes() {
   public TypeName getNativeType(final NativeTypeContext typeContext) {
     return TypeUtils.makeNullable(ReactClassNames.REACT_CALLBACK, mNullable);
   }
+
+  public MethodSpec getGeneratedMethodWithReactAnnotation(String methodName) {
+    TypeName resolvedReturnTypeName =
+        mResolvedReturnType.getNativeType(NativeTypeContext.FUNCTION_RETURN);
+
+    boolean isReturnTypePromise = resolvedReturnTypeName == ReactClassNames.REACT_PROMISE;
+    TypeName returnTypeName = isReturnTypePromise ? TypeName.VOID : resolvedReturnTypeName;
+
+    MethodSpec.Builder methodBuilder =
+        MethodSpec.methodBuilder(methodName).addModifiers(Modifier.PUBLIC);
+    methodBuilder.returns(returnTypeName);
+
+    if (!mNullable) {
+      methodBuilder.addModifiers(Modifier.ABSTRACT);
+    } else {
+      String returnStatement = getFalsyReturnStatement(returnTypeName);
+      if (returnStatement != null) {
+        CodeBlock.Builder methodBody = CodeBlock.builder();
+        methodBody.addStatement(returnStatement);
+        methodBuilder.addCode(methodBody.build());
+      }
+    }
+
+    mResolvedArgTypes
+        .entrySet()
+        .forEach(
+            e -> {
+              String argName = e.getKey();
+              ResolvedType argResolvedType = e.getValue();
+              methodBuilder.addParameter(
+                  ParameterSpec.builder(
+                          argResolvedType.getNativeType(NativeTypeContext.FUNCTION_ARGUMENT),
+                          argName)
+                      .build());
+            });
+
+    AnnotationSpec.Builder annotationBuilder = AnnotationSpec.builder(ReactClassNames.REACT_METHOD);
+
+    // Special case: Promise inserts additional method arg at the end.
+    if (isReturnTypePromise) {
+      methodBuilder.addParameter(
+          ParameterSpec.builder(ReactClassNames.REACT_PROMISE, "promise").build());
+    } else if (!TypeName.VOID.equals(returnTypeName)) {
+      // A non-promise non-void return type means the method is synchronous.
+      annotationBuilder.addMember("isBlockingSynchronousMethod", "$L", true);
+    }
+
+    // React methods need special `@ReactMethod` annotation for now.
+    methodBuilder.addAnnotation(annotationBuilder.build());
+
+    return methodBuilder.build();
+  }
+
+  private static @Nullable String getFalsyReturnStatement(TypeName returnType) {
+    if (returnType == TypeName.BOOLEAN) {
+      return "return false";
+    } else if (returnType == TypeName.DOUBLE) {
+      return "return 0.0";
+    } else if (returnType == ClassNames.STRING
+        || returnType == ReactClassNames.REACT_WRITABLE_ARRAY
+        || returnType == ReactClassNames.REACT_WRITABLE_MAP) {
+      return "return null";
+    }
+
+    return null;
+  }
 }