storage/Variant.h
author Bobby Holley <bobbyholley@gmail.com>
Sat, 01 Dec 2018 03:05:56 +0000
changeset 449094 ef8f344dca811b76a6b556d13b3aa7f5452fb5b2
parent 448947 6f3709b3878117466168c40affa7bca0b60cf75b
child 457637 466f9c24e749d7b3701b60c5ed424e586634a718
permissions -rw-r--r--
Bug 1510490 - Measure shader cache memory usage and remove total_gpu_bytes. r=mattwoodrow The latter causes confusion in the memory reports because it gets summed up and thus effectively doubles the reported texture memory usage. I've decided it's best to drop, and so might as well do that while we're already messing around with the memory reports and the associated boilerplate. Depends on D13439 Differential Revision: https://phabricator.services.mozilla.com/D13440

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_storage_Variant_h__
#define mozilla_storage_Variant_h__

#include <utility>

#include "nsIVariant.h"
#include "nsMemory.h"
#include "nsString.h"
#include "nsTArray.h"

#define VARIANT_BASE_IID                             \
  { /* 78888042-0fa3-4f7a-8b19-7996f99bf1aa */       \
    0x78888042, 0x0fa3, 0x4f7a, {                    \
      0x8b, 0x19, 0x79, 0x96, 0xf9, 0x9b, 0xf1, 0xaa \
    }                                                \
  }

/**
 * This class is used by the storage module whenever an nsIVariant needs to be
 * returned.  We provide traits for the basic sqlite types to make use easier.
 * The following types map to the indicated sqlite type:
 * int64_t   -> INTEGER (use IntegerVariant)
 * double    -> FLOAT (use FloatVariant)
 * nsString  -> TEXT (use TextVariant)
 * nsCString -> TEXT (use UTF8TextVariant)
 * uint8_t[] -> BLOB (use BlobVariant)
 * nullptr   -> NULL (use NullVariant)
 */

namespace mozilla {
namespace storage {

////////////////////////////////////////////////////////////////////////////////
//// Base Class

class Variant_base : public nsIVariant {
 public:
  NS_DECL_THREADSAFE_ISUPPORTS
  NS_DECL_NSIVARIANT
  NS_DECLARE_STATIC_IID_ACCESSOR(VARIANT_BASE_IID)

 protected:
  virtual ~Variant_base() {}
};

NS_DEFINE_STATIC_IID_ACCESSOR(Variant_base, VARIANT_BASE_IID)

////////////////////////////////////////////////////////////////////////////////
//// Traits

/**
 * Generics
 */

template <typename DataType>
struct variant_traits {
  static inline uint16_t type() { return nsIDataType::VTYPE_EMPTY; }
};

template <typename DataType, bool Adopting = false>
struct variant_storage_traits {
  typedef DataType ConstructorType;
  typedef DataType StorageType;
  static inline void storage_conversion(const ConstructorType aData,
                                        StorageType *_storage) {
    *_storage = aData;
  }

  static inline void destroy(const StorageType &_storage) {}
};

#define NO_CONVERSION return NS_ERROR_CANNOT_CONVERT_DATA;

template <typename DataType, bool Adopting = false>
struct variant_integer_traits {
  typedef typename variant_storage_traits<DataType, Adopting>::StorageType
      StorageType;
  static inline nsresult asInt32(const StorageType &, int32_t *) {
    NO_CONVERSION
  }
  static inline nsresult asInt64(const StorageType &, int64_t *) {
    NO_CONVERSION
  }
};

template <typename DataType, bool Adopting = false>
struct variant_float_traits {
  typedef typename variant_storage_traits<DataType, Adopting>::StorageType
      StorageType;
  static inline nsresult asDouble(const StorageType &, double *) {
    NO_CONVERSION
  }
};

template <typename DataType, bool Adopting = false>
struct variant_text_traits {
  typedef typename variant_storage_traits<DataType, Adopting>::StorageType
      StorageType;
  static inline nsresult asUTF8String(const StorageType &, nsACString &) {
    NO_CONVERSION
  }
  static inline nsresult asString(const StorageType &, nsAString &) {
    NO_CONVERSION
  }
};

template <typename DataType, bool Adopting = false>
struct variant_blob_traits {
  typedef typename variant_storage_traits<DataType, Adopting>::StorageType
      StorageType;
  static inline nsresult asArray(const StorageType &, uint16_t *, uint32_t *,
                                 void **) {
    NO_CONVERSION
  }
};

#undef NO_CONVERSION

/**
 * INTEGER types
 */

template <>
struct variant_traits<int64_t> {
  static inline uint16_t type() { return nsIDataType::VTYPE_INT64; }
};
template <>
struct variant_integer_traits<int64_t> {
  static inline nsresult asInt32(int64_t aValue, int32_t *_result) {
    if (aValue > INT32_MAX || aValue < INT32_MIN)
      return NS_ERROR_CANNOT_CONVERT_DATA;

    *_result = static_cast<int32_t>(aValue);
    return NS_OK;
  }
  static inline nsresult asInt64(int64_t aValue, int64_t *_result) {
    *_result = aValue;
    return NS_OK;
  }
};
// xpcvariant just calls get double for integers...
template <>
struct variant_float_traits<int64_t> {
  static inline nsresult asDouble(int64_t aValue, double *_result) {
    *_result = double(aValue);
    return NS_OK;
  }
};

/**
 * FLOAT types
 */

template <>
struct variant_traits<double> {
  static inline uint16_t type() { return nsIDataType::VTYPE_DOUBLE; }
};
template <>
struct variant_float_traits<double> {
  static inline nsresult asDouble(double aValue, double *_result) {
    *_result = aValue;
    return NS_OK;
  }
};

/**
 * TEXT types
 */

template <>
struct variant_traits<nsString> {
  static inline uint16_t type() { return nsIDataType::VTYPE_ASTRING; }
};
template <>
struct variant_storage_traits<nsString> {
  typedef const nsAString &ConstructorType;
  typedef nsString StorageType;
  static inline void storage_conversion(ConstructorType aText,
                                        StorageType *_outData) {
    *_outData = aText;
  }
  static inline void destroy(const StorageType &_outData) {}
};
template <>
struct variant_text_traits<nsString> {
  static inline nsresult asUTF8String(const nsString &aValue,
                                      nsACString &_result) {
    CopyUTF16toUTF8(aValue, _result);
    return NS_OK;
  }
  static inline nsresult asString(const nsString &aValue, nsAString &_result) {
    _result = aValue;
    return NS_OK;
  }
};

template <>
struct variant_traits<nsCString> {
  static inline uint16_t type() { return nsIDataType::VTYPE_UTF8STRING; }
};
template <>
struct variant_storage_traits<nsCString> {
  typedef const nsACString &ConstructorType;
  typedef nsCString StorageType;
  static inline void storage_conversion(ConstructorType aText,
                                        StorageType *_outData) {
    *_outData = aText;
  }
  static inline void destroy(const StorageType &aData) {}
};
template <>
struct variant_text_traits<nsCString> {
  static inline nsresult asUTF8String(const nsCString &aValue,
                                      nsACString &_result) {
    _result = aValue;
    return NS_OK;
  }
  static inline nsresult asString(const nsCString &aValue, nsAString &_result) {
    CopyUTF8toUTF16(aValue, _result);
    return NS_OK;
  }
};

/**
 * BLOB types
 */

template <>
struct variant_traits<uint8_t[]> {
  static inline uint16_t type() { return nsIDataType::VTYPE_ARRAY; }
};
template <>
struct variant_storage_traits<uint8_t[], false> {
  typedef std::pair<const void *, int> ConstructorType;
  typedef FallibleTArray<uint8_t> StorageType;
  static inline void storage_conversion(ConstructorType aBlob,
                                        StorageType *_outData) {
    _outData->Clear();
    (void)_outData->AppendElements(static_cast<const uint8_t *>(aBlob.first),
                                   aBlob.second, fallible);
  }
  static inline void destroy(const StorageType &_outData) {}
};
template <>
struct variant_storage_traits<uint8_t[], true> {
  typedef std::pair<uint8_t *, int> ConstructorType;
  typedef std::pair<uint8_t *, int> StorageType;
  static inline void storage_conversion(ConstructorType aBlob,
                                        StorageType *_outData) {
    *_outData = aBlob;
  }
  static inline void destroy(StorageType &aData) {
    if (aData.first) {
      free(aData.first);
      aData.first = nullptr;
    }
  }
};
template <>
struct variant_blob_traits<uint8_t[], false> {
  static inline nsresult asArray(FallibleTArray<uint8_t> &aData,
                                 uint16_t *_type, uint32_t *_size,
                                 void **_result) {
    // For empty blobs, we return nullptr.
    if (aData.Length() == 0) {
      *_result = nullptr;
      *_type = nsIDataType::VTYPE_UINT8;
      *_size = 0;
      return NS_OK;
    }

    // Otherwise, we copy the array.
    *_result = moz_xmemdup(aData.Elements(), aData.Length() * sizeof(uint8_t));

    // Set type and size
    *_type = nsIDataType::VTYPE_UINT8;
    *_size = aData.Length();
    return NS_OK;
  }
};

template <>
struct variant_blob_traits<uint8_t[], true> {
  static inline nsresult asArray(std::pair<uint8_t *, int> &aData,
                                 uint16_t *_type, uint32_t *_size,
                                 void **_result) {
    // For empty blobs, we return nullptr.
    if (aData.second == 0) {
      *_result = nullptr;
      *_type = nsIDataType::VTYPE_UINT8;
      *_size = 0;
      return NS_OK;
    }

    // Otherwise, transfer the data out.
    *_result = aData.first;
    aData.first = nullptr;
    MOZ_ASSERT(*_result);  // We asked for it twice, better not use adopting!

    // Set type and size
    *_type = nsIDataType::VTYPE_UINT8;
    *_size = aData.second;
    return NS_OK;
  }
};

/**
 * nullptr type
 */

class NullVariant : public Variant_base {
 public:
  uint16_t GetDataType() override { return nsIDataType::VTYPE_EMPTY; }

  NS_IMETHOD GetAsAUTF8String(nsACString &_str) override {
    // Return a void string.
    _str.SetIsVoid(true);
    return NS_OK;
  }

  NS_IMETHOD GetAsAString(nsAString &_str) override {
    // Return a void string.
    _str.SetIsVoid(true);
    return NS_OK;
  }
};

////////////////////////////////////////////////////////////////////////////////
//// Template Implementation

template <typename DataType, bool Adopting = false>
class Variant final : public Variant_base {
  ~Variant() { variant_storage_traits<DataType, Adopting>::destroy(mData); }

 public:
  explicit Variant(
      const typename variant_storage_traits<DataType, Adopting>::ConstructorType
          aData) {
    variant_storage_traits<DataType, Adopting>::storage_conversion(aData,
                                                                   &mData);
  }

  uint16_t GetDataType() override { return variant_traits<DataType>::type(); }
  NS_IMETHOD GetAsInt32(int32_t *_integer) override {
    return variant_integer_traits<DataType, Adopting>::asInt32(mData, _integer);
  }

  NS_IMETHOD GetAsInt64(int64_t *_integer) override {
    return variant_integer_traits<DataType, Adopting>::asInt64(mData, _integer);
  }

  NS_IMETHOD GetAsDouble(double *_double) override {
    return variant_float_traits<DataType, Adopting>::asDouble(mData, _double);
  }

  NS_IMETHOD GetAsAUTF8String(nsACString &_str) override {
    return variant_text_traits<DataType, Adopting>::asUTF8String(mData, _str);
  }

  NS_IMETHOD GetAsAString(nsAString &_str) override {
    return variant_text_traits<DataType, Adopting>::asString(mData, _str);
  }

  NS_IMETHOD GetAsArray(uint16_t *_type, nsIID *, uint32_t *_size,
                        void **_data) override {
    return variant_blob_traits<DataType, Adopting>::asArray(mData, _type, _size,
                                                            _data);
  }

 private:
  typename variant_storage_traits<DataType, Adopting>::StorageType mData;
};

////////////////////////////////////////////////////////////////////////////////
//// Handy typedefs!  Use these for the right mapping.

typedef Variant<int64_t> IntegerVariant;
typedef Variant<double> FloatVariant;
typedef Variant<nsString> TextVariant;
typedef Variant<nsCString> UTF8TextVariant;
typedef Variant<uint8_t[], false> BlobVariant;
typedef Variant<uint8_t[], true> AdoptedBlobVariant;

}  // namespace storage
}  // namespace mozilla

#include "Variant_inl.h"

#endif  // mozilla_storage_Variant_h__