src/developer/shell/interpreter/src/value.cc

// Copyright 2020 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/developer/shell/interpreter/src/value.h"

#include <cstdint>
#include <string>

#include "src/developer/shell/interpreter/src/interpreter.h"
#include "src/developer/shell/interpreter/src/schema.h"

namespace shell {
namespace interpreter {

String::String(Interpreter* interpreter, std::string_view value)
    : ReferenceCounted(interpreter), value_(value) {
  interpreter_->increment_string_count();
}

String::String(Interpreter* interpreter, std::string&& value)
    : ReferenceCounted(interpreter), value_(std::move(value)) {
  interpreter_->increment_string_count();
}

String::~String() { interpreter_->decrement_string_count(); }

Object::Object(Interpreter* interpreter, const std::shared_ptr<ObjectSchema> schema)
    : ReferenceCounted(interpreter), schema_(schema) {
  interpreter_->increment_object_count();
}

Object::~Object() {
  interpreter_->decrement_object_count();
  // Free all the applicative fields by assigning zero.
  for (const auto& field : schema_->fields()) {
    field->type()->SetData(reinterpret_cast<uint8_t*>(this) + field->offset(), 0,
                           /*free_old_value=*/true);
  }
}

const std::shared_ptr<ObjectSchema> Object::schema() { return schema_; }

std::unique_ptr<Value> Object::GetField(const ObjectFieldSchema* field) const {
  FX_DCHECK(field != nullptr) << "Invalid field pointer passed to getfield";
  uint64_t offset = field->offset();
  std::unique_ptr<Value> v = std::make_unique<Value>();
  const uint8_t* ptr = reinterpret_cast<const uint8_t*>(this) + offset;
  // TODO: We need to factorize this code with Type::LoadVariable.  This probably involves
  // merging ValueKind and TypeKind.
  switch (field->type()->Kind()) {
    case Type::TypeKind::kInt8:
      v->SetInt8(*reinterpret_cast<const int8_t*>(ptr));
      break;
    case Type::TypeKind::kUint8:
      v->SetUint8(*reinterpret_cast<const uint8_t*>(ptr));
      break;
    case Type::TypeKind::kInt16:
      v->SetInt16(*reinterpret_cast<const int16_t*>(ptr));
      break;
    case Type::TypeKind::kUint16:
      v->SetUint16(*reinterpret_cast<const uint16_t*>(ptr));
      break;
    case Type::TypeKind::kInt32:
      v->SetInt32(*reinterpret_cast<const int32_t*>(ptr));
      break;
    case Type::TypeKind::kUint32:
      v->SetUint32(*reinterpret_cast<const uint32_t*>(ptr));
      break;
    case Type::TypeKind::kInt64:
    case Type::TypeKind::kInteger:
      v->SetInt64(*reinterpret_cast<const int64_t*>(ptr));
      break;
    case Type::TypeKind::kUint64:
      v->SetUint64(*reinterpret_cast<const uint64_t*>(ptr));
      break;
    case Type::TypeKind::kString:
      v->SetString(*reinterpret_cast<String* const*>(ptr));
      break;
    case Type::TypeKind::kObject:
      v->SetObject(*reinterpret_cast<Object* const*>(ptr));
      break;
    default:
      FX_NOTREACHED() << "Unknown type in getfield";
      // Assert unknown type.
      break;
  }
  return v;
}

void Object::SetField(const ObjectFieldSchema* field, uint64_t value) {
  field->type()->SetData(reinterpret_cast<uint8_t*>(this) + field->offset(), value,
                         /*free_old_value=*/false);
}

void Object::Free() {
  // Call the destructor.
  this->~Object();
  // Deallocate the object using the same mechanism used to allocate it.
  delete[] reinterpret_cast<uint8_t*>(this);
}

void Value::Set(const Value& value) {
  // For types which need to take a reference, we take the reference before we release the old
  // value. This way, we don't end with a reference to a destroyed value if the user assigns a
  // value to itself.
  switch (value.type_) {
    case ValueType::kUndef:
      Release();
      break;
    case ValueType::kInt8:
      Release();
      int8_value_ = value.int8_value_;
      break;
    case ValueType::kUint8:
      Release();
      uint8_value_ = value.uint8_value_;
      break;
    case ValueType::kInt16:
      Release();
      int16_value_ = value.int16_value_;
      break;
    case ValueType::kUint16:
      Release();
      uint16_value_ = value.uint16_value_;
      break;
    case ValueType::kInt32:
      Release();
      int32_value_ = value.int32_value_;
      break;
    case ValueType::kUint32:
      Release();
      uint32_value_ = value.uint32_value_;
      break;
    case ValueType::kInt64:
      Release();
      int64_value_ = value.int64_value_;
      break;
    case ValueType::kUint64:
      Release();
      uint64_value_ = value.uint64_value_;
      break;
    case ValueType::kString: {
      String* string = value.string_->Use();
      Release();
      string_ = string;
      break;
    }
    case ValueType::kObject: {
      Object* object = value.object_->Use();
      Release();
      object_ = object;
      break;
    }
  }
  type_ = value.type_;
}

void Value::Release() {
  switch (type_) {
    case ValueType::kUndef:
    case ValueType::kInt8:
    case ValueType::kUint8:
    case ValueType::kInt16:
    case ValueType::kUint16:
    case ValueType::kInt32:
    case ValueType::kUint32:
    case ValueType::kInt64:
    case ValueType::kUint64:
      break;
    case ValueType::kString:
      string_->Release();
      break;
    case ValueType::kObject:
      object_->Release();
      break;
  }
}

}  // namespace interpreter
}  // namespace shell