mirror of
https://github.com/mozilla/gecko-dev.git
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252 lines
7.0 KiB
C++
252 lines
7.0 KiB
C++
/* 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 file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef Mappable_h
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#define Mappable_h
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#include <sys/types.h>
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#include <pthread.h>
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#include "Zip.h"
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#include "SeekableZStream.h"
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#include "mozilla/RefPtr.h"
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#include "mozilla/Scoped.h"
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#include "zlib.h"
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/**
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* Abstract class to handle mmap()ing from various kind of entities, such as
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* plain files or Zip entries. The virtual members are meant to act as the
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* equivalent system functions, with a few differences:
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* - mapped memory is always MAP_PRIVATE, even though a given implementation
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* may use something different internally.
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* - memory after length and up to the end of the corresponding page is nulled
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* out.
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*/
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class Mappable
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{
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public:
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virtual ~Mappable() { }
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virtual void *mmap(const void *addr, size_t length, int prot, int flags,
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off_t offset) = 0;
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private:
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virtual void munmap(void *addr, size_t length) {
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::munmap(addr, length);
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}
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/* Limit use of Mappable::munmap to classes that keep track of the address
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* and size of the mapping. This allows to ignore ::munmap return value. */
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friend class Mappable1stPagePtr;
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public:
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/**
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* Ensures the availability of the memory pages for the page(s) containing
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* the given address. Returns whether the pages were successfully made
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* available.
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*/
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virtual bool ensure(const void *addr) { return true; }
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/**
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* Indicate to a Mappable instance that no further mmap is going to happen.
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*/
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virtual void finalize() = 0;
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/**
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* Shows some stats about the Mappable instance.
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* Meant for MappableSeekableZStream only.
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* As Mappables don't keep track of what they are instanciated for, the name
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* argument is used to make the stats logging useful to the reader. The when
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* argument is to be used by the caller to give an identifier of the when
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* the stats call is made.
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*/
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virtual void stats(const char *when, const char *name) const { }
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};
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/**
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* Mappable implementation for plain files
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*/
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class MappableFile: public Mappable
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{
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public:
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~MappableFile() { }
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/**
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* Create a MappableFile instance for the given file path.
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*/
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static Mappable *Create(const char *path);
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/* Inherited from Mappable */
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virtual void *mmap(const void *addr, size_t length, int prot, int flags, off_t offset);
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virtual void finalize();
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protected:
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MappableFile(int fd): fd(fd) { }
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private:
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/* File descriptor */
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AutoCloseFD fd;
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};
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/**
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* Mappable implementation for deflated stream in a Zip archive
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* Inflates the complete stream into a cache file.
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*/
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class MappableExtractFile: public MappableFile
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{
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public:
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~MappableExtractFile();
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/**
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* Create a MappableExtractFile instance for the given Zip stream. The name
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* argument is used to create the cache file in the cache directory.
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*/
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static Mappable *Create(const char *name, Zip *zip, Zip::Stream *stream);
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private:
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MappableExtractFile(int fd, char *path)
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: MappableFile(fd), path(path), pid(getpid()) { }
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/**
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* AutoUnlinkFile keeps track or a file name and removes (unlinks) the file
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* when the instance is destroyed.
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*/
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struct AutoUnlinkFileTraits: public mozilla::ScopedDeleteArrayTraits<char>
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{
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static void release(char *value)
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{
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if (!value)
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return;
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unlink(value);
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mozilla::ScopedDeleteArrayTraits<char>::release(value);
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}
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};
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typedef mozilla::Scoped<AutoUnlinkFileTraits> AutoUnlinkFile;
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/* Extracted file */
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AutoUnlinkFile path;
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/* Id of the process that initialized the instance */
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pid_t pid;
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};
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class _MappableBuffer;
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/**
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* Mappable implementation for deflated stream in a Zip archive.
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* Inflates the mapped bits in a temporary buffer.
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*/
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class MappableDeflate: public Mappable
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{
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public:
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~MappableDeflate();
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/**
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* Create a MappableDeflate instance for the given Zip stream. The name
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* argument is used for an appropriately named temporary file, and the Zip
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* instance is given for the MappableDeflate to keep a reference of it.
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*/
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static Mappable *Create(const char *name, Zip *zip, Zip::Stream *stream);
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/* Inherited from Mappable */
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virtual void *mmap(const void *addr, size_t length, int prot, int flags, off_t offset);
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virtual void finalize();
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private:
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MappableDeflate(_MappableBuffer *buf, Zip *zip, Zip::Stream *stream);
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/* Zip reference */
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mozilla::RefPtr<Zip> zip;
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/* Decompression buffer */
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mozilla::ScopedDeletePtr<_MappableBuffer> buffer;
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/* Zlib data */
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z_stream zStream;
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};
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/**
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* Mappable implementation for seekable zStreams.
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* Inflates the mapped bits in a temporary buffer, on demand.
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*/
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class MappableSeekableZStream: public Mappable
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{
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public:
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~MappableSeekableZStream();
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/**
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* Create a MappableSeekableZStream instance for the given Zip stream. The
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* name argument is used for an appropriately named temporary file, and the
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* Zip instance is given for the MappableSeekableZStream to keep a reference
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* of it.
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*/
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static Mappable *Create(const char *name, Zip *zip,
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Zip::Stream *stream);
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/* Inherited from Mappable */
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virtual void *mmap(const void *addr, size_t length, int prot, int flags, off_t offset);
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virtual void munmap(void *addr, size_t length);
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virtual void finalize();
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virtual bool ensure(const void *addr);
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virtual void stats(const char *when, const char *name) const;
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private:
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MappableSeekableZStream(Zip *zip);
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/* Zip reference */
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mozilla::RefPtr<Zip> zip;
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/* Decompression buffer */
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mozilla::ScopedDeletePtr<_MappableBuffer> buffer;
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/* Seekable ZStream */
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SeekableZStream zStream;
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/* Keep track of mappings performed with MappableSeekableZStream::mmap so
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* that they can be realized by MappableSeekableZStream::ensure.
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* Values stored in the struct are those passed to mmap */
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struct LazyMap
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{
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const void *addr;
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size_t length;
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int prot;
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off_t offset;
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/* Returns addr + length, as a pointer */
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const void *end() const {
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return reinterpret_cast<const void *>
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(reinterpret_cast<const unsigned char *>(addr) + length);
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}
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/* Returns offset + length */
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const off_t endOffset() const {
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return offset + length;
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}
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/* Returns the offset corresponding to the given address */
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const off_t offsetOf(const void *ptr) const {
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return reinterpret_cast<uintptr_t>(ptr)
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- reinterpret_cast<uintptr_t>(addr) + offset;
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}
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/* Returns whether the given address is in the LazyMap range */
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const bool Contains(const void *ptr) const {
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return (ptr >= addr) && (ptr < end());
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}
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};
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/* List of all mappings */
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std::vector<LazyMap> lazyMaps;
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/* Array keeping track of which chunks have already been decompressed.
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* Each value is the number of pages decompressed for the given chunk. */
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mozilla::ScopedDeleteArray<unsigned char> chunkAvail;
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/* Number of chunks that have already been decompressed. */
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size_t chunkAvailNum;
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/* Mutex protecting decompression */
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pthread_mutex_t mutex;
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};
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#endif /* Mappable_h */
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