forked from mirrors/gecko-dev
117bb1a341
CLOSED TREE
Backed out changeset c23b8418e6be (bug 1060987)
Backed out changeset a8cddc6bdffc (bug 1061060)
Backed out changeset b5af5cbdac3f (bug 1060982)
Backed out changeset 4912d451011a (bug 1060930)
Backed out changeset bdacbf453238 (bug 1061058)
Backed out changeset da6c71a8f5ae (bug 1060987)
605 lines
17 KiB
C++
605 lines
17 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim:set ts=2 sw=2 sts=2 et cindent: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef nsScannerString_h___
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#define nsScannerString_h___
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#include "nsString.h"
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#include "nsUnicharUtils.h" // for nsCaseInsensitiveStringComparator
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#include "mozilla/LinkedList.h"
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#include <algorithm>
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/**
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* NOTE: nsScannerString (and the other classes defined in this file) are
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* not related to nsAString or any of the other xpcom/string classes.
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*
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* nsScannerString is based on the nsSlidingString implementation that used
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* to live in xpcom/string. Now that nsAString is limited to representing
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* only single fragment strings, nsSlidingString can no longer be used.
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*
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* An advantage to this design is that it does not employ any virtual
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* functions.
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*
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* This file uses SCC-style indenting in deference to the nsSlidingString
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* code from which this code is derived ;-)
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*/
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class nsScannerIterator;
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class nsScannerSubstring;
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class nsScannerString;
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/**
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* nsScannerBufferList
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*
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* This class maintains a list of heap-allocated Buffer objects. The buffers
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* are maintained in a circular linked list. Each buffer has a usage count
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* that is decremented by the owning nsScannerSubstring.
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*
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* The buffer list itself is reference counted. This allows the buffer list
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* to be shared by multiple nsScannerSubstring objects. The reference
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* counting is not threadsafe, which is not at all a requirement.
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*
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* When a nsScannerSubstring releases its reference to a buffer list, it
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* decrements the usage count of the first buffer in the buffer list that it
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* was referencing. It informs the buffer list that it can discard buffers
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* starting at that prefix. The buffer list will do so if the usage count of
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* that buffer is 0 and if it is the first buffer in the list. It will
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* continue to prune buffers starting from the front of the buffer list until
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* it finds a buffer that has a usage count that is non-zero.
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*/
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class nsScannerBufferList
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{
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public:
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/**
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* Buffer objects are directly followed by a data segment. The start
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* of the data segment is determined by increment the |this| pointer
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* by 1 unit.
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*/
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class Buffer : public mozilla::LinkedListElement<Buffer>
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{
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public:
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void IncrementUsageCount() { ++mUsageCount; }
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void DecrementUsageCount() { --mUsageCount; }
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bool IsInUse() const { return mUsageCount != 0; }
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const char16_t* DataStart() const { return (const char16_t*) (this+1); }
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char16_t* DataStart() { return ( char16_t*) (this+1); }
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const char16_t* DataEnd() const { return mDataEnd; }
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char16_t* DataEnd() { return mDataEnd; }
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const Buffer* Next() const { return getNext(); }
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Buffer* Next() { return getNext(); }
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const Buffer* Prev() const { return getPrevious(); }
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Buffer* Prev() { return getPrevious(); }
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uint32_t DataLength() const { return mDataEnd - DataStart(); }
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void SetDataLength(uint32_t len) { mDataEnd = DataStart() + len; }
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private:
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friend class nsScannerBufferList;
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int32_t mUsageCount;
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char16_t* mDataEnd;
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};
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/**
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* Position objects serve as lightweight pointers into a buffer list.
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* The mPosition member must be contained with mBuffer->DataStart()
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* and mBuffer->DataEnd().
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*/
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class Position
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{
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public:
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Position() {}
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Position( Buffer* buffer, char16_t* position )
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: mBuffer(buffer)
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, mPosition(position)
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{}
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inline
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Position( const nsScannerIterator& aIter );
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inline
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Position& operator=( const nsScannerIterator& aIter );
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static size_t Distance( const Position& p1, const Position& p2 );
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Buffer* mBuffer;
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char16_t* mPosition;
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};
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static Buffer* AllocBufferFromString( const nsAString& );
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static Buffer* AllocBuffer( uint32_t capacity ); // capacity = number of chars
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nsScannerBufferList( Buffer* buf )
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: mRefCnt(0)
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{
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mBuffers.insertBack(buf);
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}
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void AddRef() { ++mRefCnt; }
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void Release() { if (--mRefCnt == 0) delete this; }
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void Append( Buffer* buf ) { mBuffers.insertBack(buf); }
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void InsertAfter( Buffer* buf, Buffer* prev ) { prev->setNext(buf); }
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void SplitBuffer( const Position& );
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void DiscardUnreferencedPrefix( Buffer* );
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Buffer* Head() { return mBuffers.getFirst(); }
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const Buffer* Head() const { return mBuffers.getFirst(); }
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Buffer* Tail() { return mBuffers.getLast(); }
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const Buffer* Tail() const { return mBuffers.getLast(); }
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private:
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friend class nsScannerSubstring;
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~nsScannerBufferList() { ReleaseAll(); }
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void ReleaseAll();
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int32_t mRefCnt;
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mozilla::LinkedList<Buffer> mBuffers;
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};
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/**
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* nsScannerFragment represents a "slice" of a Buffer object.
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*/
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struct nsScannerFragment
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{
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typedef nsScannerBufferList::Buffer Buffer;
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const Buffer* mBuffer;
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const char16_t* mFragmentStart;
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const char16_t* mFragmentEnd;
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};
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/**
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* nsScannerSubstring is the base class for nsScannerString. It provides
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* access to iterators and methods to bind the substring to another
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* substring or nsAString instance.
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*
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* This class owns the buffer list.
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*/
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class nsScannerSubstring
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{
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public:
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typedef nsScannerBufferList::Buffer Buffer;
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typedef nsScannerBufferList::Position Position;
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typedef uint32_t size_type;
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nsScannerSubstring();
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nsScannerSubstring( const nsAString& s );
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~nsScannerSubstring();
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nsScannerIterator& BeginReading( nsScannerIterator& iter ) const;
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nsScannerIterator& EndReading( nsScannerIterator& iter ) const;
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size_type Length() const { return mLength; }
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int32_t CountChar( char16_t ) const;
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void Rebind( const nsScannerSubstring&, const nsScannerIterator&, const nsScannerIterator& );
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void Rebind( const nsAString& );
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const nsSubstring& AsString() const;
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bool GetNextFragment( nsScannerFragment& ) const;
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bool GetPrevFragment( nsScannerFragment& ) const;
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static inline Buffer* AllocBufferFromString( const nsAString& aStr ) { return nsScannerBufferList::AllocBufferFromString(aStr); }
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static inline Buffer* AllocBuffer( size_type aCapacity ) { return nsScannerBufferList::AllocBuffer(aCapacity); }
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protected:
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void acquire_ownership_of_buffer_list() const
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{
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mBufferList->AddRef();
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mStart.mBuffer->IncrementUsageCount();
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}
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void release_ownership_of_buffer_list()
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{
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if (mBufferList)
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{
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mStart.mBuffer->DecrementUsageCount();
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mBufferList->DiscardUnreferencedPrefix(mStart.mBuffer);
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mBufferList->Release();
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}
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}
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void init_range_from_buffer_list()
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{
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mStart.mBuffer = mBufferList->Head();
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mStart.mPosition = mStart.mBuffer->DataStart();
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mEnd.mBuffer = mBufferList->Tail();
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mEnd.mPosition = mEnd.mBuffer->DataEnd();
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mLength = Position::Distance(mStart, mEnd);
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}
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Position mStart;
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Position mEnd;
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nsScannerBufferList *mBufferList;
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size_type mLength;
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// these fields are used to implement AsString
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nsDependentSubstring mFlattenedRep;
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bool mIsDirty;
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friend class nsScannerSharedSubstring;
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};
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/**
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* nsScannerString provides methods to grow and modify a buffer list.
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*/
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class nsScannerString : public nsScannerSubstring
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{
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public:
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nsScannerString( Buffer* );
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// you are giving ownership to the string, it takes and keeps your
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// buffer, deleting it when done.
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// Use AllocBuffer or AllocBufferFromString to create a Buffer object
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// for use with this function.
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void AppendBuffer( Buffer* );
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void DiscardPrefix( const nsScannerIterator& );
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// any other way you want to do this?
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void UngetReadable(const nsAString& aReadable, const nsScannerIterator& aCurrentPosition);
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void ReplaceCharacter(nsScannerIterator& aPosition, char16_t aChar);
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};
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/**
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* nsScannerSharedSubstring implements copy-on-write semantics for
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* nsScannerSubstring. When you call .writable(), it will copy the data
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* and return a mutable string object. This class also manages releasing
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* the reference to the scanner buffer when it is no longer needed.
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*/
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class nsScannerSharedSubstring
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{
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public:
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nsScannerSharedSubstring()
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: mBuffer(nullptr), mBufferList(nullptr) { }
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~nsScannerSharedSubstring()
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{
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if (mBufferList)
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ReleaseBuffer();
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}
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// Acquire a copy-on-write reference to the given substring.
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void Rebind(const nsScannerIterator& aStart,
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const nsScannerIterator& aEnd);
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// Get a mutable reference to this string
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nsSubstring& writable()
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{
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if (mBufferList)
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MakeMutable();
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return mString;
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}
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// Get a const reference to this string
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const nsSubstring& str() const { return mString; }
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private:
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typedef nsScannerBufferList::Buffer Buffer;
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void ReleaseBuffer();
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void MakeMutable();
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nsDependentSubstring mString;
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Buffer *mBuffer;
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nsScannerBufferList *mBufferList;
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};
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/**
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* nsScannerIterator works just like nsReadingIterator<CharT> except that
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* it knows how to iterate over a list of scanner buffers.
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*/
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class nsScannerIterator
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{
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public:
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typedef nsScannerIterator self_type;
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typedef ptrdiff_t difference_type;
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typedef char16_t value_type;
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typedef const char16_t* pointer;
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typedef const char16_t& reference;
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typedef nsScannerSubstring::Buffer Buffer;
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protected:
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nsScannerFragment mFragment;
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const char16_t* mPosition;
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const nsScannerSubstring* mOwner;
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friend class nsScannerSubstring;
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friend class nsScannerSharedSubstring;
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public:
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nsScannerIterator() {}
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// nsScannerIterator( const nsScannerIterator& ); // auto-generated copy-constructor OK
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// nsScannerIterator& operator=( const nsScannerIterator& ); // auto-generated copy-assignment operator OK
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inline void normalize_forward();
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inline void normalize_backward();
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pointer get() const
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{
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return mPosition;
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}
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char16_t operator*() const
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{
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return *get();
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}
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const nsScannerFragment& fragment() const
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{
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return mFragment;
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}
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const Buffer* buffer() const
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{
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return mFragment.mBuffer;
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}
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self_type& operator++()
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{
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++mPosition;
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normalize_forward();
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return *this;
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}
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self_type operator++( int )
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{
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self_type result(*this);
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++mPosition;
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normalize_forward();
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return result;
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}
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self_type& operator--()
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{
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normalize_backward();
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--mPosition;
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return *this;
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}
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self_type operator--( int )
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{
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self_type result(*this);
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normalize_backward();
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--mPosition;
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return result;
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}
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difference_type size_forward() const
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{
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return mFragment.mFragmentEnd - mPosition;
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}
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difference_type size_backward() const
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{
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return mPosition - mFragment.mFragmentStart;
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}
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self_type& advance( difference_type n )
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{
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while ( n > 0 )
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{
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difference_type one_hop = std::min(n, size_forward());
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NS_ASSERTION(one_hop>0, "Infinite loop: can't advance a reading iterator beyond the end of a string");
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// perhaps I should |break| if |!one_hop|?
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mPosition += one_hop;
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normalize_forward();
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n -= one_hop;
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}
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while ( n < 0 )
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{
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normalize_backward();
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difference_type one_hop = std::max(n, -size_backward());
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NS_ASSERTION(one_hop<0, "Infinite loop: can't advance (backward) a reading iterator beyond the end of a string");
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// perhaps I should |break| if |!one_hop|?
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mPosition += one_hop;
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n -= one_hop;
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}
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return *this;
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}
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};
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inline
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bool
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SameFragment( const nsScannerIterator& a, const nsScannerIterator& b )
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{
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return a.fragment().mFragmentStart == b.fragment().mFragmentStart;
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}
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/**
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* this class is needed in order to make use of the methods in nsAlgorithm.h
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*/
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template <>
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struct nsCharSourceTraits<nsScannerIterator>
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{
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typedef nsScannerIterator::difference_type difference_type;
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static
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uint32_t
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readable_distance( const nsScannerIterator& first, const nsScannerIterator& last )
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{
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return uint32_t(SameFragment(first, last) ? last.get() - first.get() : first.size_forward());
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}
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static
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const nsScannerIterator::value_type*
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read( const nsScannerIterator& iter )
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{
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return iter.get();
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}
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static
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void
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advance( nsScannerIterator& s, difference_type n )
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{
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s.advance(n);
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}
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};
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/**
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* inline methods follow
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*/
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inline
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void
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nsScannerIterator::normalize_forward()
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{
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while (mPosition == mFragment.mFragmentEnd && mOwner->GetNextFragment(mFragment))
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mPosition = mFragment.mFragmentStart;
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}
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inline
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void
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nsScannerIterator::normalize_backward()
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{
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while (mPosition == mFragment.mFragmentStart && mOwner->GetPrevFragment(mFragment))
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mPosition = mFragment.mFragmentEnd;
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}
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inline
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bool
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operator==( const nsScannerIterator& lhs, const nsScannerIterator& rhs )
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{
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return lhs.get() == rhs.get();
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}
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inline
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bool
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operator!=( const nsScannerIterator& lhs, const nsScannerIterator& rhs )
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{
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return lhs.get() != rhs.get();
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}
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inline
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nsScannerBufferList::Position::Position(const nsScannerIterator& aIter)
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: mBuffer(const_cast<Buffer*>(aIter.buffer()))
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, mPosition(const_cast<char16_t*>(aIter.get()))
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{}
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inline
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nsScannerBufferList::Position&
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nsScannerBufferList::Position::operator=(const nsScannerIterator& aIter)
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{
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mBuffer = const_cast<Buffer*>(aIter.buffer());
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mPosition = const_cast<char16_t*>(aIter.get());
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return *this;
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}
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/**
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* scanner string utils
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*
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* These methods mimic the API provided by nsReadableUtils in xpcom/string.
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* Here we provide only the methods that the htmlparser module needs.
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*/
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inline
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size_t
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Distance( const nsScannerIterator& aStart, const nsScannerIterator& aEnd )
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{
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typedef nsScannerBufferList::Position Position;
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return Position::Distance(Position(aStart), Position(aEnd));
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}
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void
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CopyUnicodeTo( const nsScannerIterator& aSrcStart,
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const nsScannerIterator& aSrcEnd,
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nsAString& aDest );
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inline
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void
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CopyUnicodeTo( const nsScannerSubstring& aSrc, nsAString& aDest )
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{
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nsScannerIterator begin, end;
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CopyUnicodeTo(aSrc.BeginReading(begin), aSrc.EndReading(end), aDest);
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}
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void
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AppendUnicodeTo( const nsScannerIterator& aSrcStart,
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const nsScannerIterator& aSrcEnd,
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nsAString& aDest );
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inline
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void
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AppendUnicodeTo( const nsScannerSubstring& aSrc, nsAString& aDest )
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{
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nsScannerIterator begin, end;
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AppendUnicodeTo(aSrc.BeginReading(begin), aSrc.EndReading(end), aDest);
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}
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void
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AppendUnicodeTo( const nsScannerIterator& aSrcStart,
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const nsScannerIterator& aSrcEnd,
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nsScannerSharedSubstring& aDest );
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bool
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|
FindCharInReadable( char16_t aChar,
|
|
nsScannerIterator& aStart,
|
|
const nsScannerIterator& aEnd );
|
|
|
|
bool
|
|
FindInReadable( const nsAString& aPattern,
|
|
nsScannerIterator& aStart,
|
|
nsScannerIterator& aEnd,
|
|
const nsStringComparator& = nsDefaultStringComparator() );
|
|
|
|
bool
|
|
RFindInReadable( const nsAString& aPattern,
|
|
nsScannerIterator& aStart,
|
|
nsScannerIterator& aEnd,
|
|
const nsStringComparator& = nsDefaultStringComparator() );
|
|
|
|
inline
|
|
bool
|
|
CaseInsensitiveFindInReadable( const nsAString& aPattern,
|
|
nsScannerIterator& aStart,
|
|
nsScannerIterator& aEnd )
|
|
{
|
|
return FindInReadable(aPattern, aStart, aEnd,
|
|
nsCaseInsensitiveStringComparator());
|
|
}
|
|
|
|
#endif // !defined(nsScannerString_h___)
|