Initial commit of the FlatBuffers code.

Change-Id: I4c9f0f722490b374257adb3fec63e44ae93da920
Tested: using VS2010 / Xcode / gcc on Linux.

src/idl_gen_java.cpp

@@ -0,0 +1,399 @@
+/*
+ * 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"
+
+#ifdef _WIN32
+#include <direct.h>
+#define PATH_SEPARATOR "\\"
+#define mkdir(n, m) _mkdir(n)
+#else
+#include <sys/stat.h>
+#define PATH_SEPARATOR "/"
+#endif
+
+namespace flatbuffers {
+namespace java {
+
+static std::string GenTypeBasic(const Type &type) {
+  static const char *ctypename[] = {
+    #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE) #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";
+  }
+}
+
+// Convert an underscore_based_indentifier in to camelCase.
+// Also uppercases the first character if first is true.
+static std::string MakeCamel(const std::string &in, bool first = true) {
+  std::string s;
+  for (size_t i = 0; i < in.length(); i++) {
+    if (!i && first) s += toupper(in[0]);
+    else if (in[i] == '_' && i + 1 < in.length()) s += toupper(in[++i]);
+    else s += in[i];
+  }
+  return s;
+}
+
+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) + ", 0);\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(StructDef &struct_def,
+                      std::string *code_ptr,
+                      StructDef *root_struct_def) {
+  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 == root_struct_def) {
+    // Generate a special accessor for the table that has been declared as
+    // the root type.
+    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";
+  }
+  // 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";
+  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 + i)";
+            code += ", bb) : null";
+          }
+          break;
+        case BASE_TYPE_STRING:
+          code += offset_prefix + getter +"(o) : 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);
+      code += " " + MakeCamel(field.name, false) + ") { builder.add";
+      code += GenMethod(field) + "(";
+      code += NumToString(it - struct_def.fields.vec.begin()) + ", ";
+      code += MakeCamel(field.name, false) + ", " + 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(";
+        code += NumToString(InlineSize(field.value.type));
+        code += ", numElems); }\n";
+      }
+    }
+    code += "  public static int end" + struct_def.name;
+    code += "(FlatBufferBuilder builder) { return builder.endObject(); }\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) {
+  if (!classcode.length()) return true;
+
+  std::string name_space_java;
+  std::string name_space_dir = path;
+  for (auto it = parser.name_space_.begin();
+        it != parser.name_space_.end(); ++it) {
+    if (name_space_java.length()) {
+      name_space_java += ".";
+      name_space_dir += PATH_SEPARATOR;
+    }
+    name_space_java += *it;
+    name_space_dir += *it;
+    mkdir(name_space_dir.c_str(), S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH);
+  }
+
+  std::string code = "// automatically generated, do not modify\n\n";
+  code += "package " + name_space_java + ";\n\n";
+  code += "import java.nio.*;\nimport java.lang.*;\nimport java.util.*;\n";
+  code += "import flatbuffers.*;\n\n";
+  code += classcode;
+  auto filename = name_space_dir + PATH_SEPARATOR + 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) {
+  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))
+      return false;
+  }
+
+  for (auto it = parser.structs_.vec.begin();
+       it != parser.structs_.vec.end(); ++it) {
+    std::string declcode;
+    GenStruct(**it, &declcode, parser.root_struct_def);
+    if (!SaveClass(parser, **it, declcode, path))
+      return false;
+  }
+
+  return true;
+}
+
+}  // namespace flatbuffers
+