gecko/storage/src/Variant.h

411 lines
11 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is
* Mozilla Corporation
* Portions created by the Initial Developer are Copyright (C) 2008
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Shawn Wilsher <me@shawnwilsher.com> (Original Author)
* Drew Willcoxon <adw@mozilla.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef mozilla_storage_Variant_h__
#define mozilla_storage_Variant_h__
#include <utility>
#include "nsIVariant.h"
#include "nsString.h"
#include "nsTArray.h"
/**
* 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:
* PRInt64 -> INTEGER (use IntegerVariant)
* double -> FLOAT (use FloatVariant)
* nsString -> TEXT (use TextVariant)
* nsCString -> TEXT (use UTF8TextVariant)
* PRUint8[] -> BLOB (use BlobVariant)
* nsnull -> NULL (use NullVariant)
*/
namespace mozilla {
namespace storage {
////////////////////////////////////////////////////////////////////////////////
//// Base Class
class Variant_base : public nsIVariant
{
public:
NS_DECL_ISUPPORTS
NS_DECL_NSIVARIANT
protected:
virtual ~Variant_base() { }
};
////////////////////////////////////////////////////////////////////////////////
//// Traits
/**
* Generics
*/
template <typename DataType>
struct variant_traits
{
static inline PRUint16 type() { return nsIDataType::VTYPE_EMPTY; }
};
template <typename DataType>
struct variant_storage_traits
{
typedef DataType ConstructorType;
typedef DataType StorageType;
static inline StorageType storage_conversion(ConstructorType aData) { return aData; }
};
#define NO_CONVERSION return NS_ERROR_CANNOT_CONVERT_DATA;
template <typename DataType>
struct variant_integer_traits
{
typedef typename variant_storage_traits<DataType>::StorageType StorageType;
static inline nsresult asInt32(StorageType, PRInt32 *) { NO_CONVERSION }
static inline nsresult asInt64(StorageType, PRInt64 *) { NO_CONVERSION }
};
template <typename DataType>
struct variant_float_traits
{
typedef typename variant_storage_traits<DataType>::StorageType StorageType;
static inline nsresult asDouble(StorageType, double *) { NO_CONVERSION }
};
template <typename DataType>
struct variant_text_traits
{
typedef typename variant_storage_traits<DataType>::StorageType StorageType;
static inline nsresult asUTF8String(StorageType, nsACString &) { NO_CONVERSION }
static inline nsresult asString(StorageType, nsAString &) { NO_CONVERSION }
};
template <typename DataType>
struct variant_blob_traits
{
typedef typename variant_storage_traits<DataType>::StorageType StorageType;
static inline nsresult asArray(StorageType, PRUint16 *, PRUint32 *, void **)
{ NO_CONVERSION }
};
#undef NO_CONVERSION
/**
* INTEGER types
*/
template < >
struct variant_traits<PRInt64>
{
static inline PRUint16 type() { return nsIDataType::VTYPE_INT64; }
};
template < >
struct variant_integer_traits<PRInt64>
{
static inline nsresult asInt32(PRInt64 aValue,
PRInt32 *_result)
{
if (aValue > PR_INT32_MAX || aValue < PR_INT32_MIN)
return NS_ERROR_CANNOT_CONVERT_DATA;
*_result = static_cast<PRInt32>(aValue);
return NS_OK;
}
static inline nsresult asInt64(PRInt64 aValue,
PRInt64 *_result)
{
*_result = aValue;
return NS_OK;
}
};
// xpcvariant just calls get double for integers...
template < >
struct variant_float_traits<PRInt64>
{
static inline nsresult asDouble(PRInt64 aValue,
double *_result)
{
*_result = double(aValue);
return NS_OK;
}
};
/**
* FLOAT types
*/
template < >
struct variant_traits<double>
{
static inline PRUint16 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 PRUint16 type() { return nsIDataType::VTYPE_ASTRING; }
};
template < >
struct variant_storage_traits<nsString>
{
typedef const nsAString & ConstructorType;
typedef nsString StorageType;
static inline StorageType storage_conversion(ConstructorType aText)
{
return StorageType(aText);
}
};
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 PRUint16 type() { return nsIDataType::VTYPE_UTF8STRING; }
};
template < >
struct variant_storage_traits<nsCString>
{
typedef const nsACString & ConstructorType;
typedef nsCString StorageType;
static inline StorageType storage_conversion(ConstructorType aText)
{
return StorageType(aText);
}
};
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<PRUint8[]>
{
static inline PRUint16 type() { return nsIDataType::VTYPE_ARRAY; }
};
template < >
struct variant_storage_traits<PRUint8[]>
{
typedef std::pair<const void *, int> ConstructorType;
typedef nsTArray<PRUint8> StorageType;
static inline StorageType storage_conversion(ConstructorType aBlob)
{
nsTArray<PRUint8> data(aBlob.second);
(void)data.AppendElements(static_cast<const PRUint8 *>(aBlob.first),
aBlob.second);
return data;
}
};
template < >
struct variant_blob_traits<PRUint8[]>
{
static inline nsresult asArray(nsTArray<PRUint8> &aData,
PRUint16 *_type,
PRUint32 *_size,
void **_result)
{
// For empty blobs, we return nsnull.
if (aData.Length() == 0) {
*_result = nsnull;
*_type = nsIDataType::VTYPE_UINT8;
*_size = 0;
return NS_OK;
}
// Otherwise, we copy the array.
*_result = nsMemory::Clone(aData.Elements(), aData.Length() * sizeof(PRUint8));
NS_ENSURE_TRUE(*_result, NS_ERROR_OUT_OF_MEMORY);
// Set type and size
*_type = nsIDataType::VTYPE_UINT8;
*_size = aData.Length();
return NS_OK;
}
};
/**
* NULL type
*/
class NullVariant : public Variant_base
{
public:
NS_IMETHOD GetDataType(PRUint16 *_type)
{
NS_ENSURE_ARG_POINTER(_type);
*_type = nsIDataType::VTYPE_EMPTY;
return NS_OK;
}
NS_IMETHOD GetAsAUTF8String(nsACString &_str)
{
// Return a void string.
_str.Truncate(0);
_str.SetIsVoid(PR_TRUE);
return NS_OK;
}
NS_IMETHOD GetAsAString(nsAString &_str)
{
// Return a void string.
_str.Truncate(0);
_str.SetIsVoid(PR_TRUE);
return NS_OK;
}
};
////////////////////////////////////////////////////////////////////////////////
//// Template Implementation
template <typename DataType>
class Variant : public Variant_base
{
public:
Variant(typename variant_storage_traits<DataType>::ConstructorType aData)
: mData(variant_storage_traits<DataType>::storage_conversion(aData))
{
}
NS_IMETHOD GetDataType(PRUint16 *_type)
{
*_type = variant_traits<DataType>::type();
return NS_OK;
}
NS_IMETHOD GetAsInt32(PRInt32 *_integer)
{
return variant_integer_traits<DataType>::asInt32(mData, _integer);
}
NS_IMETHOD GetAsInt64(PRInt64 *_integer)
{
return variant_integer_traits<DataType>::asInt64(mData, _integer);
}
NS_IMETHOD GetAsDouble(double *_double)
{
return variant_float_traits<DataType>::asDouble(mData, _double);
}
NS_IMETHOD GetAsAUTF8String(nsACString &_str)
{
return variant_text_traits<DataType>::asUTF8String(mData, _str);
}
NS_IMETHOD GetAsAString(nsAString &_str)
{
return variant_text_traits<DataType>::asString(mData, _str);
}
NS_IMETHOD GetAsArray(PRUint16 *_type,
nsIID *,
PRUint32 *_size,
void **_data)
{
return variant_blob_traits<DataType>::asArray(mData, _type, _size, _data);
}
private:
typename variant_storage_traits<DataType>::StorageType mData;
};
////////////////////////////////////////////////////////////////////////////////
//// Handy typedefs! Use these for the right mapping.
typedef Variant<PRInt64> IntegerVariant;
typedef Variant<double> FloatVariant;
typedef Variant<nsString> TextVariant;
typedef Variant<nsCString> UTF8TextVariant;
typedef Variant<PRUint8[]> BlobVariant;
} // namespace storage
} // namespace mozilla
#include "Variant_inl.h"
#endif // mozilla_storage_Variant_h__