/*

* Copyright 2014 Google Inc. All rights reserved.

*

* 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.

*/

// independent from idl_parser, since this code is not needed for most clients

#include "flatbuffers/flatbuffers.h"

#include "flatbuffers/idl.h"

#include "flatbuffers/util.h"

namespace flatbuffers {

namespace java {

static std::string GenTypeBasic(const Type &type) {

static const char *ctypename[] = {

#define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE) #JTYPE,

FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)

#undef FLATBUFFERS_TD

};

return ctypename[type.base_type];

}

static std::string GenTypeGet(const Type &type);

static std::string GenTypePointer(const Type &type) {

switch (type.base_type) {

case BASE_TYPE_STRING:

return "String";

case BASE_TYPE_VECTOR:

return GenTypeGet(type.VectorType());

case BASE_TYPE_STRUCT:

return type.struct_def->name;

case BASE_TYPE_UNION:

// fall through

default:

return "Table";

}

}

static std::string GenTypeGet(const Type &type) {

return IsScalar(type.base_type)

? GenTypeBasic(type)

: GenTypePointer(type);

}

static void GenComment(const std::string &dc,

std::string *code_ptr,

const char *prefix = "") {

std::string &code = *code_ptr;

if (dc.length()) {

code += std::string(prefix) + "///" + dc + "\n";

}

}

static void GenEnum(EnumDef &enum_def, std::string *code_ptr) {

std::string &code = *code_ptr;

if (enum_def.generated) return;

// Generate enum definitions of the form:

// public static final int name = value;

// We use ints rather than the Java Enum feature, because we want them

// to map directly to how they're used in C/C++ and file formats.

// That, and Java Enums are expensive, and not universally liked.

GenComment(enum_def.doc_comment, code_ptr);

code += "public class " + enum_def.name + " {\n";

for (auto it = enum_def.vals.vec.begin();

it != enum_def.vals.vec.end();

++it) {

auto &ev = **it;

GenComment(ev.doc_comment, code_ptr, " ");

code += " public static final " + GenTypeBasic(enum_def.underlying_type);

code += " " + ev.name + " = ";

code += NumToString(ev.value) + ";\n";

}

code += "};\n\n";

}

// Returns the function name that is able to read a value of the given type.

static std::string GenGetter(const Type &type) {

switch (type.base_type) {

case BASE_TYPE_STRING: return "__string";

case BASE_TYPE_STRUCT: return "__struct";

case BASE_TYPE_UNION: return "__union";

case BASE_TYPE_VECTOR: return GenGetter(type.VectorType());

default:

return "bb.get" + (SizeOf(type.base_type) > 1

? MakeCamel(GenTypeGet(type))

: "");

}

}

// Returns the method name for use with add/put calls.

static std::string GenMethod(const FieldDef &field) {

return IsScalar(field.value.type.base_type)

? MakeCamel(GenTypeBasic(field.value.type))

: (IsStruct(field.value.type) ? "Struct" : "Offset");

}

// Recursively generate arguments for a constructor, to deal with nested

// structs.

static void GenStructArgs(const StructDef &struct_def, std::string *code_ptr,

const char *nameprefix) {

std::string &code = *code_ptr;

for (auto it = struct_def.fields.vec.begin();

it != struct_def.fields.vec.end();

++it) {

auto &field = **it;

if (IsStruct(field.value.type)) {

// Generate arguments for a struct inside a struct. To ensure names

// don't clash, and to make it obvious these arguments are constructing

// a nested struct, prefix the name with the struct name.

GenStructArgs(*field.value.type.struct_def, code_ptr,

(field.value.type.struct_def->name + "_").c_str());

} else {

code += ", " + GenTypeBasic(field.value.type) + " " + nameprefix;

code += MakeCamel(field.name, false);

}

}

}

// Recusively generate struct construction statements of the form:

// builder.putType(name);

// and insert manual padding.

static void GenStructBody(const StructDef &struct_def, std::string *code_ptr,

const char *nameprefix) {

std::string &code = *code_ptr;

code += " builder.prep(" + NumToString(struct_def.minalign) + ", ";

code += NumToString(struct_def.bytesize) + ");\n";

for (auto it = struct_def.fields.vec.rbegin();

it != struct_def.fields.vec.rend();

++it) {

auto &field = **it;

if (field.padding)

code += " builder.pad(" + NumToString(field.padding) + ");\n";

if (IsStruct(field.value.type)) {

GenStructBody(*field.value.type.struct_def, code_ptr,

(field.value.type.struct_def->name + "_").c_str());

} else {

code += " builder.put" + GenMethod(field) + "(";

code += nameprefix + MakeCamel(field.name, false) + ");\n";

}

}

}

static void GenStruct(const Parser &parser, StructDef &struct_def,

std::string *code_ptr) {

if (struct_def.generated) return;

std::string &code = *code_ptr;

// Generate a struct accessor class, with methods of the form:

// public type name() { return bb.getType(i + offset); }

// or for tables of the form:

// public type name() {

// int o = __offset(offset); return o != 0 ? bb.getType(o + i) : default;

// }

GenComment(struct_def.doc_comment, code_ptr);

code += "public class " + struct_def.name + " extends ";

code += struct_def.fixed ? "Struct" : "Table";

code += " {\n";

if (!struct_def.fixed) {

// Generate a special accessor for the table that when used as the root

// of a FlatBuffer

code += " public static " + struct_def.name + " getRootAs";

code += struct_def.name;

code += "(ByteBuffer _bb, int offset) { ";

code += "_bb.order(ByteOrder.LITTLE_ENDIAN); ";

code += "return (new " + struct_def.name;

code += "()).__init(_bb.getInt(offset) + offset, _bb); }\n";

if (parser.root_struct_def == &struct_def) {

if (parser.file_identifier_.length()) {

// Check if a buffer has the identifier.

code += " public static boolean " + struct_def.name;

code += "BufferHasIdentifier(ByteBuffer _bb, int offset) { return ";

code += "__has_identifier(_bb, offset, \"" + parser.file_identifier_;

code += "\"); }\n";

}

}

}

// Generate the __init method that sets the field in a pre-existing

// accessor object. This is to allow object reuse.

code += " public " + struct_def.name;

code += " __init(int _i, ByteBuffer _bb) ";

code += "{ bb_pos = _i; bb = _bb; return this; }\n\n";

for (auto it = struct_def.fields.vec.begin();

it != struct_def.fields.vec.end();

++it) {

auto &field = **it;

if (field.deprecated) continue;

GenComment(field.doc_comment, code_ptr, " ");

std::string type_name = GenTypeGet(field.value.type);

std::string method_start = " public " + type_name + " " +

MakeCamel(field.name, false);

// Generate the accessors that don't do object reuse.

if (field.value.type.base_type == BASE_TYPE_STRUCT) {

// Calls the accessor that takes an accessor object with a new object.

code += method_start + "() { return " + MakeCamel(field.name, false);

code += "(new ";

code += type_name + "()); }\n";

} else if (field.value.type.base_type == BASE_TYPE_VECTOR &&

field.value.type.element == BASE_TYPE_STRUCT) {

// Accessors for vectors of structs also take accessor objects, this

// generates a variant without that argument.

code += method_start + "(int j) { return " + MakeCamel(field.name, false);

code += "(new ";

code += type_name + "(), j); }\n";

}

std::string getter = GenGetter(field.value.type);

code += method_start + "(";

// Most field accessors need to retrieve and test the field offset first,

// this is the prefix code for that:

auto offset_prefix = ") { int o = __offset(" +

NumToString(field.value.offset) +

"); return o != 0 ? ";

if (IsScalar(field.value.type.base_type)) {

if (struct_def.fixed) {

code += ") { return " + getter;

code += "(bb_pos + " + NumToString(field.value.offset) + ")";

} else {

code += offset_prefix + getter;

code += "(o + bb_pos) : " + field.value.constant;

}

} else {

switch (field.value.type.base_type) {

case BASE_TYPE_STRUCT:

code += type_name + " obj";

if (struct_def.fixed) {

code += ") { return obj.__init(bb_pos + ";

code += NumToString(field.value.offset) + ", bb)";

} else {

code += offset_prefix;

code += "obj.__init(";

code += field.value.type.struct_def->fixed

? "o + bb_pos"

: "__indirect(o + bb_pos)";

code += ", bb) : null";

}

break;

case BASE_TYPE_STRING:

code += offset_prefix + getter +"(o + bb_pos) : null";

break;

case BASE_TYPE_VECTOR: {

auto vectortype = field.value.type.VectorType();

if (vectortype.base_type == BASE_TYPE_STRUCT) {

code += type_name + " obj, ";

getter = "obj.__init";

}

code += "int j" + offset_prefix + getter +"(";

auto index = "__vector(o) + j * " +

NumToString(InlineSize(vectortype));

if (vectortype.base_type == BASE_TYPE_STRUCT) {

code += vectortype.struct_def->fixed

? index

: "__indirect(" + index + ")";

code += ", bb";

} else {

code += index;

}

code += ") : ";

code += IsScalar(field.value.type.element) ? "0" : "null";

break;

}

case BASE_TYPE_UNION:

code += type_name + " obj" + offset_prefix + getter;

code += "(obj, o) : null";

break;

default:

assert(0);

}

}

code += "; }\n";

if (field.value.type.base_type == BASE_TYPE_VECTOR) {

code += " public int " + MakeCamel(field.name, false) + "Length(";

code += offset_prefix;

code += "__vector_len(o) : 0; }\n";

}

}

code += "\n";

if (struct_def.fixed) {

// create a struct constructor function

code += " public static int create" + struct_def.name;

code += "(FlatBufferBuilder builder";

GenStructArgs(struct_def, code_ptr, "");

code += ") {\n";

GenStructBody(struct_def, code_ptr, "");

code += " return builder.offset();\n }\n";

} else {

// Create a set of static methods that allow table construction,

// of the form:

// public static void addName(FlatBufferBuilder builder, short name)

// { builder.addShort(id, name, default); }

code += " public static void start" + struct_def.name;

code += "(FlatBufferBuilder builder) { builder.startObject(";

code += NumToString(struct_def.fields.vec.size()) + "); }\n";

for (auto it = struct_def.fields.vec.begin();

it != struct_def.fields.vec.end();

++it) {

auto &field = **it;

if (field.deprecated) continue;

code += " public static void add" + MakeCamel(field.name);

code += "(FlatBufferBuilder builder, " + GenTypeBasic(field.value.type);

auto argname = MakeCamel(field.name, false);

if (!IsScalar(field.value.type.base_type)) argname += "Offset";

code += " " + argname + ") { builder.add";

code += GenMethod(field) + "(";

code += NumToString(it - struct_def.fields.vec.begin()) + ", ";

code += argname + ", " + field.value.constant;

code += "); }\n";

if (field.value.type.base_type == BASE_TYPE_VECTOR) {

code += " public static void start" + MakeCamel(field.name);

code += "Vector(FlatBufferBuilder builder, int numElems) ";

code += "{ builder.startVector(";

auto vector_type = field.value.type.VectorType();

auto alignment = InlineAlignment(vector_type);

auto elem_size = InlineSize(vector_type);

code += NumToString(elem_size);

code += ", numElems, " + NumToString(alignment);

code += "); }\n";

}

}

code += " public static int end" + struct_def.name;

code += "(FlatBufferBuilder builder) { return builder.endObject(); }\n";

if (parser.root_struct_def == &struct_def) {

code += " public static void finish" + struct_def.name;

code += "Buffer(FlatBufferBuilder builder, int offset) { ";

code += "builder.finish(offset";

if (parser.file_identifier_.length())

code += ", \"" + parser.file_identifier_ + "\"";

code += "); }\n";

}

}

code += "};\n\n";

}

// Save out the generated code for a single Java class while adding

// declaration boilerplate.

static bool SaveClass(const Parser &parser, const Definition &def,

const std::string &classcode, const std::string &path,

bool needs_imports) {

if (!classcode.length()) return true;

std::string namespace_java;

std::string namespace_dir = path;

auto &namespaces = parser.namespaces_.back()->components;

for (auto it = namespaces.begin(); it != namespaces.end(); ++it) {

if (namespace_java.length()) {

namespace_java += ".";

namespace_dir += kPathSeparator;

}

namespace_java += *it;

namespace_dir += *it;

}

EnsureDirExists(namespace_dir);

std::string code = "// automatically generated, do not modify\n\n";

code += "package " + namespace_java + ";\n\n";

if (needs_imports) {

code += "import java.nio.*;\nimport java.lang.*;\nimport java.util.*;\n";

code += "import flatbuffers.*;\n\n";

}

code += classcode;

auto filename = namespace_dir + kPathSeparator + def.name + ".java";

return SaveFile(filename.c_str(), code, false);

}

} // namespace java

bool GenerateJava(const Parser &parser,

const std::string &path,

const std::string & /*file_name*/,

const GeneratorOptions & /*opts*/) {

using namespace java;

for (auto it = parser.enums_.vec.begin();

it != parser.enums_.vec.end(); ++it) {

std::string enumcode;

GenEnum(**it, &enumcode);

if (!SaveClass(parser, **it, enumcode, path, false))

return false;

}

for (auto it = parser.structs_.vec.begin();

it != parser.structs_.vec.end(); ++it) {

std::string declcode;

GenStruct(parser, **it, &declcode);

if (!SaveClass(parser, **it, declcode, path, true))

return false;

}

return true;

}

} // namespace flatbuffers