gecko-dev/storage/Variant.h
Marco Bonardo 1b86f6b5be Bug 483318 - Implement binding arrays to mozIStorageStatementParams. r=asuth,lina,Standard8
Use `carray`` extension to bind array of numerics and strings, so we can
avoid large and slow IN clauses, and cache prepared statements having
a variable number of parameters.
The extension is statically loaded and available in every connection.
Consumers are encouraged to use the explicit `bindArrayXXX` methods, as
the generic `bindByIndex` and `bindByName` methods are too lenient,
especially from Javascript.
Note `carray`` only supports UTF8 encoded strings, the API will convert
the encoding when UTF16 is passed in.
These new variants are not exposed to Rust yet, as the existing comment
suggests they were intended for primitive types. It could be done in the
future, if necessary.

Differential Revision: https://phabricator.services.mozilla.com/D225334
2024-10-28 19:28:24 +00:00

522 lines
20 KiB
C++

/* -*- 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 "nsIInterfaceRequestor.h"
#include "nsIVariant.h"
#include "nsCOMPtr.h"
#include "nsString.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)
* int64_t[] -> ARRAY (use ArrayOfIntegersVariant)
* double[] -> ARRAY (use ArrayOfDoublesVariant)
* nsCString[] -> ARRAY (use ArrayOfUTF8StringsVariant)
*
* The kvstore component also reuses this class as a common implementation
* of a simple threadsafe variant for the storage of primitive values only.
* The BooleanVariant type has been introduced for kvstore use cases and should
* be enhanced to provide full boolean variant support for mozStorage.
*
* Bug 1494102 tracks that work.
*/
namespace mozilla::storage {
////////////////////////////////////////////////////////////////////////////////
//// Base Class
class Variant_base : public nsIVariant, public nsIInterfaceRequestor {
public:
NS_DECL_THREADSAFE_ISUPPORTS
NS_DECL_NSIVARIANT
NS_DECLARE_STATIC_IID_ACCESSOR(VARIANT_BASE_IID)
NS_IMETHOD
GetInterface(const nsIID& aIID, void** aResult) override {
NS_ENSURE_ARG_POINTER(aResult);
*aResult = nullptr;
// This is used to recognize nsIVariant instances derived from Variant_base
// from other implementations like XPCVariant that may not be thread-safe.
if (aIID.Equals(VARIANT_BASE_IID) || aIID.Equals(NS_GET_IID(nsIVariant))) {
nsCOMPtr<nsIVariant> result(static_cast<nsIVariant*>(this));
result.forget(aResult);
return NS_OK;
}
return NS_NOINTERFACE;
}
protected:
virtual ~Variant_base() = default;
};
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 {
using ConstructorType = DataType;
using StorageType = DataType;
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_boolean_traits {
using StorageType =
typename variant_storage_traits<DataType, Adopting>::StorageType;
static inline nsresult asBool(const StorageType&, bool*) { NO_CONVERSION }
};
template <typename DataType, bool Adopting = false>
struct variant_integer_traits {
using StorageType =
typename variant_storage_traits<DataType, Adopting>::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 {
using StorageType =
typename variant_storage_traits<DataType, Adopting>::StorageType;
static inline nsresult asDouble(const StorageType&, double*) { NO_CONVERSION }
};
template <typename DataType, bool Adopting = false>
struct variant_text_traits {
using StorageType =
typename variant_storage_traits<DataType, Adopting>::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_array_traits {
using StorageType =
typename variant_storage_traits<DataType, Adopting>::StorageType;
static inline nsresult asArray(const StorageType&, uint16_t*, uint32_t*,
void**) {
NO_CONVERSION
}
};
#undef NO_CONVERSION
/**
* BOOLEAN type
*/
template <>
struct variant_traits<bool> {
static inline uint16_t type() { return nsIDataType::VTYPE_BOOL; }
};
template <>
struct variant_boolean_traits<bool> {
static inline nsresult asBool(bool aValue, bool* _result) {
*_result = aValue;
return NS_OK;
}
// NB: It might be worth also providing conversions to int types.
// NB: It'd be nice to implement asBool conversions for 0 and 1, too.
// That would let us clean up some conversions in Places, such as:
// https://searchfox.org/mozilla-central/rev/0640ea80fbc8d48f8b197cd363e2535c95a15eb3/toolkit/components/places/SQLFunctions.cpp#564-565
// https://searchfox.org/mozilla-central/rev/0640ea80fbc8d48f8b197cd363e2535c95a15eb3/toolkit/components/places/SQLFunctions.cpp#1057
// https://searchfox.org/mozilla-central/rev/0640ea80fbc8d48f8b197cd363e2535c95a15eb3/toolkit/components/places/nsNavHistory.cpp#3189
};
/**
* 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> {
using ConstructorType = const nsAString&;
using StorageType = nsString;
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> {
using ConstructorType = const nsACString&;
using StorageType = nsCString;
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;
}
};
/**
* ARRAY types
*/
// NOLINTBEGIN(bugprone-macro-parentheses)
#define SPECIALIZE_ARRAY_TO_NUMERIC_VARIANT(Type, DataType) \
template <> \
struct variant_traits<Type[]> { \
static inline uint16_t type() { return nsIDataType::VTYPE_ARRAY; } \
}; \
\
template <> \
struct variant_storage_traits<Type[], false> { \
using ConstructorType = std::pair<const void*, int>; \
using StorageType = FallibleTArray<Type>; \
static inline void storage_conversion(ConstructorType aArrayAndLength, \
StorageType* _outData) { \
_outData->Clear(); \
MOZ_ALWAYS_TRUE(_outData->AppendElements( \
static_cast<const Type*>(aArrayAndLength.first), \
aArrayAndLength.second, fallible)); \
} \
static inline void destroy(const StorageType& _outData) {} \
}; \
\
template <> \
struct variant_storage_traits<Type[], true> { \
using ConstructorType = std::pair<Type*, int>; \
using StorageType = std::pair<Type*, int>; \
static inline void storage_conversion(ConstructorType aArrayAndLength, \
StorageType* _outData) { \
*_outData = aArrayAndLength; \
} \
static inline void destroy(StorageType& aArrayAndLength) { \
if (aArrayAndLength.first) { \
free(aArrayAndLength.first); \
aArrayAndLength.first = nullptr; \
} \
} \
}; \
\
template <> \
struct variant_array_traits<Type[], false> { \
static inline nsresult asArray(FallibleTArray<Type>& aData, \
uint16_t* _type, uint32_t* _size, \
void** _result) { \
/* For empty arrays, we return nullptr. */ \
if (aData.Length() == 0) { \
*_result = nullptr; \
*_type = DataType; \
*_size = 0; \
return NS_OK; \
} \
/* Otherwise, we copy the array. */ \
*_result = moz_xmemdup(aData.Elements(), aData.Length() * sizeof(Type)); \
*_type = DataType; \
*_size = aData.Length(); \
return NS_OK; \
} \
}; \
\
template <> \
struct variant_array_traits<Type[], true> { \
static inline nsresult asArray(std::pair<Type*, int>& aData, \
uint16_t* _type, uint32_t* _size, \
void** _result) { \
/* For empty arrays, we return nullptr. */ \
if (aData.second == 0) { \
*_result = nullptr; \
*_type = DataType; \
*_size = 0; \
return NS_OK; \
} \
/* Otherwise, transfer the data out. */ \
*_result = aData.first; \
aData.first = nullptr; \
/* If we asked for it twice, better not use adopting! */ \
MOZ_ASSERT(*_result); \
*_type = DataType; \
*_size = aData.second; \
return NS_OK; \
} \
}
// NOLINTEND(bugprone-macro-parentheses)
SPECIALIZE_ARRAY_TO_NUMERIC_VARIANT(uint8_t, nsIDataType::VTYPE_UINT8);
SPECIALIZE_ARRAY_TO_NUMERIC_VARIANT(int64_t, nsIDataType::VTYPE_INT64);
SPECIALIZE_ARRAY_TO_NUMERIC_VARIANT(double, nsIDataType::VTYPE_DOUBLE);
template <>
struct variant_traits<nsCString[]> {
static inline uint16_t type() { return nsIDataType::VTYPE_ARRAY; }
};
template <>
struct variant_storage_traits<nsCString[], false> {
using ConstructorType = std::pair<const void*, int>;
using StorageType = FallibleTArray<nsCString>;
static inline void storage_conversion(ConstructorType aArrayAndLength,
StorageType* _outData) {
_outData->Clear();
if (!_outData->SetCapacity(aArrayAndLength.second, fallible)) {
MOZ_ASSERT_UNREACHABLE("Cannot allocate.");
return;
}
// We can avoid copying the strings as we're asking SQLite to do it on bind
// by using SQLITE_TRANSIENT.
const nsCString* str = static_cast<const nsCString*>(aArrayAndLength.first);
for (int32_t i = 0; i < aArrayAndLength.second; ++i, str++) {
MOZ_ALWAYS_TRUE(_outData->AppendElement(*str, fallible));
}
}
static inline void destroy(const StorageType& _outData) {}
};
template <>
struct variant_array_traits<nsCString[], false> {
static inline nsresult asArray(FallibleTArray<nsCString>& aData,
uint16_t* _type, uint32_t* _size,
void** _result) {
// For empty arrays, we return nullptr.
if (aData.Length() == 0) {
*_result = nullptr;
*_type = nsIDataType::VTYPE_UTF8STRING;
*_size = 0;
return NS_OK;
}
// Otherwise, we copy the array.
// This memory will be freed up after Sqlite made its own copy in
// sqlite3_T_array. The string buffers are owned by mData.
const char** strings =
(const char**)moz_xmalloc(sizeof(char*) * aData.Length());
const char** iter = strings;
for (const nsCString& str : aData) {
*iter = str.get();
iter++;
}
*_result = strings;
*_type = nsIDataType::VTYPE_UTF8STRING;
*_size = aData.Length();
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 GetAsBool(bool* _boolean) override {
return variant_boolean_traits<DataType, Adopting>::asBool(mData, _boolean);
}
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_array_traits<DataType, Adopting>::asArray(mData, _type,
_size, _data);
}
protected:
typename variant_storage_traits<DataType, Adopting>::StorageType mData;
};
////////////////////////////////////////////////////////////////////////////////
//// Handy typedefs! Use these for the right mapping.
// Currently, BooleanVariant is only useful for kvstore.
// Bug 1494102 tracks implementing full boolean variant support for mozStorage.
using BooleanVariant = Variant<bool>;
using IntegerVariant = Variant<int64_t>;
using FloatVariant = Variant<double>;
using TextVariant = Variant<nsString>;
using UTF8TextVariant = Variant<nsCString>;
using BlobVariant = Variant<uint8_t[], false>;
using AdoptedBlobVariant = Variant<uint8_t[], true>;
using ArrayOfIntegersVariant = Variant<int64_t[], false>;
using AdoptedArrayOfIntegersVariant = Variant<int64_t[], true>;
using ArrayOfDoublesVariant = Variant<double[], false>;
using AdoptedArrayOfDoublesVariant = Variant<double[], true>;
using ArrayOfUTF8StringsVariant = Variant<nsCString[], false>;
} // namespace mozilla::storage
#include "Variant_inl.h"
#endif // mozilla_storage_Variant_h__