src/com/facebook/buck/parcelable/Generator.java - buck - Git at Google

 /*
  * Copyright 2012-present Facebook, Inc.
  *
  * 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.facebook.buck.parcelable;

 import com.google.common.base.Function;
 import com.google.common.base.Joiner;
 import com.google.common.base.Preconditions;
 import com.google.common.base.Splitter;
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Iterables;

 import java.io.File;
 import java.io.IOException;
 import java.util.Map;

 import javax.annotation.Nullable;

 public class Generator {

   private final ParcelableClass clazz;

   public Generator(ParcelableClass clazz) {
     this.clazz = Preconditions.checkNotNull(clazz);
   }

   public static String generateFromFile(File file) throws IOException {
     ParcelableClass parcelableClass = Parser.parse(file);
     return new Generator(parcelableClass).generate();
   }

   public String generate() throws IOException {
     PrintfStringBuilder out = new PrintfStringBuilder();

     out.appendLines(
         "/*",
         " * DO NOT MODIFY.",
         " * This file was auto-generated by Buck.",
         " */");

     out.appendLine("package %s;\n", clazz.getPackageName());

     for (String importLine : clazz.getImports()) {
       out.appendLine(importLine);
     }
     out.append('\n');

     String classDeclaration = clazz.getClassName();
     if (clazz.hasSuperClass()) {
       classDeclaration += " extends " + clazz.getSuperClassName();
     }
     out.appendLine("public class %s implements Parcelable {\n", classDeclaration);

     insertFields(out);

     // Jackson and other de-serializers often require a no-arg constructor.
     insertEmptyConstructor(out);

     insertFieldBasedConstructor(out);
     insertParcelBasedConstructor(out);
     insertDescribeContents(out);
     insertWriteToParcel(out);
     insertCreator(out);

     // Close top-level class definition.
     out.appendLine("}");

     return out.toString();
   }

   private void insertFields(PrintfStringBuilder out) throws IOException {
     final String defaultFieldVisibility = clazz.getDefaultFieldVisibility();
     for (ParcelableField field : clazz.getFields()) {
       if (field.getJsonProperty() != null) {
         String jsonProperty = field.getJsonProperty().isEmpty()
             ? ""
             : String.format("(\"%s\")", field.getJsonProperty());
         out.appendLine("  @JsonProperty%s", jsonProperty);
       }

       String visibility = field.getVisibility();
       if (visibility == null) {
         visibility = defaultFieldVisibility;
       }
       if (!visibility.isEmpty()) {
         visibility += ' ';
       }

       String mutability = field.isMutable() ? "" : "final ";
       out.appendLine("  %s%s%s %s;",
           visibility,
           mutability,
           field.getType(),
           field.getName());
       out.append('\n');
     }
   }

   private static final Map<String, String> TYPE_TO_DEFAULT_VALUE =
       ImmutableMap.<String, String>builder()
           .put("byte", "0")
           .put("int", "0")
           .put("long", "0")
           .put("float", "0")
           .put("double", "0")
           .put("boolean", "false")
           .build();

   private void insertEmptyConstructor(PrintfStringBuilder out) throws IOException {
     out.appendLine("  public %s() {", clazz.getClassName());
     if (clazz.hasSuperClass()) {
       out.appendLine("    super();");
     }

     for (ParcelableField field : clazz.getFields()) {
       String defaultValue = field.getDefaultValue();
       if (defaultValue == null) {
         defaultValue = TYPE_TO_DEFAULT_VALUE.get(field.getType());
         if (defaultValue == null) {
           defaultValue = "null";
         }
       }
       out.appendLine("    this.%s = %s;", field.getName(), defaultValue);
     }
     out.appendLine("  }");
     out.append('\n');
   }

   private void insertFieldBasedConstructor(PrintfStringBuilder out) throws IOException {
     out.appendLine("  public %s(", clazz.getClassName());

     if (clazz.hasSuperClass()) {
       String rawSuperParams = Strings.nullToEmpty(clazz.getRawSuperParams());
       if (!rawSuperParams.isEmpty() && !rawSuperParams.endsWith(",")) {
         rawSuperParams += ",";
       }
       out.appendLine("      %s", rawSuperParams);
     }

     final String defaultFieldVisibility = clazz.getDefaultFieldVisibility();
     Joiner.on(",\n").appendTo(out, Iterables.transform(clazz.getFields(),
         new Function<ParcelableField, String>() {

       @Override
       public String apply(ParcelableField field) {
         String visibility = field.getVisibility();
         if (visibility == null) {
           visibility = defaultFieldVisibility;
         }

         return String.format("      %s %s", field.getType(), field.getName());
       }

     }));

     // Close the param list and open the body.
     out.appendLine(") {");
     if (clazz.hasSuperClass()) {
       // rawSuperParams will be of the form "boolean isMale, int age".
       // They need to be filtered into param names to pass to super().
       String rawSuperParams = Strings.nullToEmpty(clazz.getRawSuperParams());
       String superParamNames = Joiner.on(", ").join(Iterables.transform(
           Splitter.on(',').trimResults().omitEmptyStrings().split(rawSuperParams),
           new Function<String, String>() {
             @Override
             public String apply(String typeAndName) {
               return typeAndName.split("\\s+")[1];
             }
           }));

       out.appendLine("    super(%s);", superParamNames);
     }

     for (ParcelableField field : clazz.getFields()) {
       out.appendLine("    this.%s = %s;", field.getName(), field.getName());
     }

     // Close constructor body.
     out.appendLine("  }");
   }

   private static final Map<String, ReadWriteMethod> SIMPLE_TYPE_MAPPINGS =
       ImmutableMap.<String, ReadWriteMethod>builder()
           .put("byte", ReadWriteMethod.both("Byte"))
           .put("double", ReadWriteMethod.both("Double"))
           .put("float", ReadWriteMethod.both("Float"))
           .put("int", ReadWriteMethod.both("Int"))
           .put("long", ReadWriteMethod.both("Long"))
           .put("String", ReadWriteMethod.both("String"))
           .put("List<String>", new ReadWriteMethod("createStringArrayList", "writeStringList"))
           .put("String[]", new ReadWriteMethod("createStringArray", "writeStringArray"))
           .build();

   private void insertParcelBasedConstructor(PrintfStringBuilder out) throws IOException {
     out.append('\n');
     out.appendLine("  public %s(Parcel parcel) {", clazz.getClassName());
     if (clazz.hasSuperClass()) {
       out.appendLine("    super(parcel);");
     }

     for (ParcelableField field : clazz.getFields()) {
       String type = field.getType();
       String fieldName = field.getName();
       ReadWriteMethod readWriteMethod = SIMPLE_TYPE_MAPPINGS.get(type);
       if (readWriteMethod != null && readWriteMethod.hasReadMethod()) {
         out.appendLine("    this.%s = parcel.%s();", fieldName, readWriteMethod.readMethod);
       } else if ("boolean".equals(type)) {
         out.appendLine("    this.%s = parcel.readByte() != 0;", fieldName);
       } else if ("List".equals(type)) {
         // If we do not have any type information, then we cannot use readTypedList().
         out.appendLine("    this.%s = parcel.readArrayList(null /* classLoader */);", fieldName);
       } else if (type.startsWith("List<")) {
         String genericType = type.substring("List<".length(), type.length() - 1);
         // We prefer readTypedList when we have type information, as it ostensibly stricter for
         // checking. May need to revisit this if the genericType is a supertype that has subclasses
         // with their own CREATOR that should be used.
         out.appendLine("    this.%s = Lists.newArrayList();", fieldName);
         out.appendLine("    parcel.readTypedList(this.%s, %s.CREATOR);", fieldName, genericType);
       } else {
         out.appendLine("    this.%s = parcel.readParcelable(%s.class.getClassLoader());",
             fieldName,
             field.getType());
       }
     }
     out.appendLine("  }");
   }

   private void insertDescribeContents(PrintfStringBuilder out) throws IOException {
     out.append('\n');
     out.appendLines(
         "  @Override",
         "  public int describeContents() {",
         "    return 0;",
         "  }");
   }

   private void insertWriteToParcel(PrintfStringBuilder out) throws IOException {
     out.append('\n');
     out.appendLines(
         "  @Override",
         "  public void writeToParcel(Parcel dest, int flags) {");
     for (ParcelableField field : clazz.getFields()) {
       String type = field.getType();
       String fieldName = field.getName();
       ReadWriteMethod readWriteMethod = SIMPLE_TYPE_MAPPINGS.get(type);
       if (readWriteMethod != null && readWriteMethod.hasWriteMethod()) {
         out.appendLine("    dest.%s(this.%s);", readWriteMethod.writeMethod, fieldName);
       } else if ("boolean".equals(type)) {
         out.appendLine("    dest.writeByte((byte)(this.%s ? 1 : 0));", fieldName);
       } else if ("List".equals(type)) {
         out.appendLine("    dest.writeList(this.%s);", fieldName);
       } else if (type.startsWith("List<")) {
         out.appendLine("    dest.writeTypedList(this.%s);", fieldName);
       } else {
         // Everything else is assumed to be a Parcelable.
         // This heuristic could be incorrect, so it will have to be improved over time.
         out.appendLine("    dest.writeParcelable(this.%s, flags);", fieldName);
       }
     }
     out.appendLines("  }");
   }

   private void insertCreator(PrintfStringBuilder out) throws IOException {
     out.append('\n');

     String creatorClassName = clazz.getCreatorClassName();
     out.appendLine("  public static final Parcelable.Creator<%s> CREATOR = " +
     		"new Parcelable.Creator<%s>() {",
     		creatorClassName,
     		creatorClassName);
     out.appendLine("    public %s createFromParcel(Parcel in) {", creatorClassName);
     out.appendLine("      return new %s(in);", creatorClassName);
     out.appendLine("    }");
     out.appendLine("    public %s[] newArray(int size) {", creatorClassName);
     out.appendLine("      return new %s[size];", creatorClassName);
     out.appendLine("    }");
     out.appendLine("  };");
   }

   private static class ReadWriteMethod {
     @Nullable private final String readMethod;
     @Nullable private final String writeMethod;

     private ReadWriteMethod(String readMethod, String writeMethod) {
       this.readMethod = readMethod;
       this.writeMethod = writeMethod;
     }

     public static ReadWriteMethod both(String name) {
       return new ReadWriteMethod("read" + name, "write" + name);
     }

     public boolean hasReadMethod() {
       return readMethod != null;
     }

     public boolean hasWriteMethod() {
       return writeMethod != null;
     }
   }
 }
	/*
	* Copyright 2012-present Facebook, Inc.
	*
	* 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.facebook.buck.parcelable;

	import com.google.common.base.Function;
	import com.google.common.base.Joiner;
	import com.google.common.base.Preconditions;
	import com.google.common.base.Splitter;
	import com.google.common.base.Strings;
	import com.google.common.collect.ImmutableMap;
	import com.google.common.collect.Iterables;

	import java.io.File;
	import java.io.IOException;
	import java.util.Map;

	import javax.annotation.Nullable;

	public class Generator {

	private final ParcelableClass clazz;

	public Generator(ParcelableClass clazz) {
	this.clazz = Preconditions.checkNotNull(clazz);
	}

	public static String generateFromFile(File file) throws IOException {
	ParcelableClass parcelableClass = Parser.parse(file);
	return new Generator(parcelableClass).generate();
	}

	public String generate() throws IOException {
	PrintfStringBuilder out = new PrintfStringBuilder();

	out.appendLines(
	"/*",
	" * DO NOT MODIFY.",
	" * This file was auto-generated by Buck.",
	" */");

	out.appendLine("package %s;\n", clazz.getPackageName());

	for (String importLine : clazz.getImports()) {
	out.appendLine(importLine);
	}
	out.append('\n');

	String classDeclaration = clazz.getClassName();
	if (clazz.hasSuperClass()) {
	classDeclaration += " extends " + clazz.getSuperClassName();
	}
	out.appendLine("public class %s implements Parcelable {\n", classDeclaration);

	insertFields(out);

	// Jackson and other de-serializers often require a no-arg constructor.
	insertEmptyConstructor(out);

	insertFieldBasedConstructor(out);
	insertParcelBasedConstructor(out);
	insertDescribeContents(out);
	insertWriteToParcel(out);
	insertCreator(out);

	// Close top-level class definition.
	out.appendLine("}");

	return out.toString();
	}

	private void insertFields(PrintfStringBuilder out) throws IOException {
	final String defaultFieldVisibility = clazz.getDefaultFieldVisibility();
	for (ParcelableField field : clazz.getFields()) {
	if (field.getJsonProperty() != null) {
	String jsonProperty = field.getJsonProperty().isEmpty()
	? ""
	: String.format("(\"%s\")", field.getJsonProperty());
	out.appendLine(" @JsonProperty%s", jsonProperty);
	}

	String visibility = field.getVisibility();
	if (visibility == null) {
	visibility = defaultFieldVisibility;
	}
	if (!visibility.isEmpty()) {
	visibility += ' ';
	}

	String mutability = field.isMutable() ? "" : "final ";
	out.appendLine(" %s%s%s %s;",
	visibility,
	mutability,
	field.getType(),
	field.getName());
	out.append('\n');
	}
	}

	private static final Map<String, String> TYPE_TO_DEFAULT_VALUE =
	ImmutableMap.<String, String>builder()
	.put("byte", "0")
	.put("int", "0")
	.put("long", "0")
	.put("float", "0")
	.put("double", "0")
	.put("boolean", "false")
	.build();

	private void insertEmptyConstructor(PrintfStringBuilder out) throws IOException {
	out.appendLine(" public %s() {", clazz.getClassName());
	if (clazz.hasSuperClass()) {
	out.appendLine(" super();");
	}

	for (ParcelableField field : clazz.getFields()) {
	String defaultValue = field.getDefaultValue();
	if (defaultValue == null) {
	defaultValue = TYPE_TO_DEFAULT_VALUE.get(field.getType());
	if (defaultValue == null) {
	defaultValue = "null";
	}
	}
	out.appendLine(" this.%s = %s;", field.getName(), defaultValue);
	}
	out.appendLine(" }");
	out.append('\n');
	}

	private void insertFieldBasedConstructor(PrintfStringBuilder out) throws IOException {
	out.appendLine(" public %s(", clazz.getClassName());

	if (clazz.hasSuperClass()) {
	String rawSuperParams = Strings.nullToEmpty(clazz.getRawSuperParams());
	if (!rawSuperParams.isEmpty() && !rawSuperParams.endsWith(",")) {
	rawSuperParams += ",";
	}
	out.appendLine(" %s", rawSuperParams);
	}

	final String defaultFieldVisibility = clazz.getDefaultFieldVisibility();
	Joiner.on(",\n").appendTo(out, Iterables.transform(clazz.getFields(),
	new Function<ParcelableField, String>() {

	@Override
	public String apply(ParcelableField field) {
	String visibility = field.getVisibility();
	if (visibility == null) {
	visibility = defaultFieldVisibility;
	}

	return String.format(" %s %s", field.getType(), field.getName());
	}

	}));

	// Close the param list and open the body.
	out.appendLine(") {");
	if (clazz.hasSuperClass()) {
	// rawSuperParams will be of the form "boolean isMale, int age".
	// They need to be filtered into param names to pass to super().
	String rawSuperParams = Strings.nullToEmpty(clazz.getRawSuperParams());
	String superParamNames = Joiner.on(", ").join(Iterables.transform(
	Splitter.on(',').trimResults().omitEmptyStrings().split(rawSuperParams),
	new Function<String, String>() {
	@Override
	public String apply(String typeAndName) {
	return typeAndName.split("\\s+")[1];
	}
	}));

	out.appendLine(" super(%s);", superParamNames);
	}

	for (ParcelableField field : clazz.getFields()) {
	out.appendLine(" this.%s = %s;", field.getName(), field.getName());
	}

	// Close constructor body.
	out.appendLine(" }");
	}

	private static final Map<String, ReadWriteMethod> SIMPLE_TYPE_MAPPINGS =
	ImmutableMap.<String, ReadWriteMethod>builder()
	.put("byte", ReadWriteMethod.both("Byte"))
	.put("double", ReadWriteMethod.both("Double"))
	.put("float", ReadWriteMethod.both("Float"))
	.put("int", ReadWriteMethod.both("Int"))
	.put("long", ReadWriteMethod.both("Long"))
	.put("String", ReadWriteMethod.both("String"))
	.put("List<String>", new ReadWriteMethod("createStringArrayList", "writeStringList"))
	.put("String[]", new ReadWriteMethod("createStringArray", "writeStringArray"))
	.build();

	private void insertParcelBasedConstructor(PrintfStringBuilder out) throws IOException {
	out.append('\n');
	out.appendLine(" public %s(Parcel parcel) {", clazz.getClassName());
	if (clazz.hasSuperClass()) {
	out.appendLine(" super(parcel);");
	}

	for (ParcelableField field : clazz.getFields()) {
	String type = field.getType();
	String fieldName = field.getName();
	ReadWriteMethod readWriteMethod = SIMPLE_TYPE_MAPPINGS.get(type);
	if (readWriteMethod != null && readWriteMethod.hasReadMethod()) {
	out.appendLine(" this.%s = parcel.%s();", fieldName, readWriteMethod.readMethod);
	} else if ("boolean".equals(type)) {
	out.appendLine(" this.%s = parcel.readByte() != 0;", fieldName);
	} else if ("List".equals(type)) {
	// If we do not have any type information, then we cannot use readTypedList().
	out.appendLine(" this.%s = parcel.readArrayList(null /* classLoader */);", fieldName);
	} else if (type.startsWith("List<")) {
	String genericType = type.substring("List<".length(), type.length() - 1);
	// We prefer readTypedList when we have type information, as it ostensibly stricter for
	// checking. May need to revisit this if the genericType is a supertype that has subclasses
	// with their own CREATOR that should be used.
	out.appendLine(" this.%s = Lists.newArrayList();", fieldName);
	out.appendLine(" parcel.readTypedList(this.%s, %s.CREATOR);", fieldName, genericType);
	} else {
	out.appendLine(" this.%s = parcel.readParcelable(%s.class.getClassLoader());",
	fieldName,
	field.getType());
	}
	}
	out.appendLine(" }");
	}

	private void insertDescribeContents(PrintfStringBuilder out) throws IOException {
	out.append('\n');
	out.appendLines(
	" @Override",
	" public int describeContents() {",
	" return 0;",
	" }");
	}

	private void insertWriteToParcel(PrintfStringBuilder out) throws IOException {
	out.append('\n');
	out.appendLines(
	" @Override",
	" public void writeToParcel(Parcel dest, int flags) {");
	for (ParcelableField field : clazz.getFields()) {
	String type = field.getType();
	String fieldName = field.getName();
	ReadWriteMethod readWriteMethod = SIMPLE_TYPE_MAPPINGS.get(type);
	if (readWriteMethod != null && readWriteMethod.hasWriteMethod()) {
	out.appendLine(" dest.%s(this.%s);", readWriteMethod.writeMethod, fieldName);
	} else if ("boolean".equals(type)) {
	out.appendLine(" dest.writeByte((byte)(this.%s ? 1 : 0));", fieldName);
	} else if ("List".equals(type)) {
	out.appendLine(" dest.writeList(this.%s);", fieldName);
	} else if (type.startsWith("List<")) {
	out.appendLine(" dest.writeTypedList(this.%s);", fieldName);
	} else {
	// Everything else is assumed to be a Parcelable.
	// This heuristic could be incorrect, so it will have to be improved over time.
	out.appendLine(" dest.writeParcelable(this.%s, flags);", fieldName);
	}
	}
	out.appendLines(" }");
	}

	private void insertCreator(PrintfStringBuilder out) throws IOException {
	out.append('\n');

	String creatorClassName = clazz.getCreatorClassName();
	out.appendLine(" public static final Parcelable.Creator<%s> CREATOR = " +
	"new Parcelable.Creator<%s>() {",
	creatorClassName,
	creatorClassName);
	out.appendLine(" public %s createFromParcel(Parcel in) {", creatorClassName);
	out.appendLine(" return new %s(in);", creatorClassName);
	out.appendLine(" }");
	out.appendLine(" public %s[] newArray(int size) {", creatorClassName);
	out.appendLine(" return new %s[size];", creatorClassName);
	out.appendLine(" }");
	out.appendLine(" };");
	}

	private static class ReadWriteMethod {
	@Nullable private final String readMethod;
	@Nullable private final String writeMethod;

	private ReadWriteMethod(String readMethod, String writeMethod) {
	this.readMethod = readMethod;
	this.writeMethod = writeMethod;
	}

	public static ReadWriteMethod both(String name) {
	return new ReadWriteMethod("read" + name, "write" + name);
	}

	public boolean hasReadMethod() {
	return readMethod != null;
	}

	public boolean hasWriteMethod() {
	return writeMethod != null;
	}
	}
	}