The Tor Browser: comparison mozglue/linker/Mappable.h

--1:000000000000
+:ad48036de94c
+/* 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 Mappable_h
+#define Mappable_h
+#include <sys/types.h>
+#include <pthread.h>
+#include "Zip.h"
+#include "SeekableZStream.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/Scoped.h"
+#include "zlib.h"
+/**
+* Abstract class to handle mmap()ing from various kind of entities, such as
+* plain files or Zip entries. The virtual members are meant to act as the
+* equivalent system functions, except mapped memory is always MAP_PRIVATE,
+* even though a given implementation may use something different internally.
+*/
+class Mappable: public mozilla::RefCounted<Mappable>
+{
+public:
+MOZ_DECLARE_REFCOUNTED_TYPENAME(Mappable)
+virtual ~Mappable() { }
+virtual MemoryRange mmap(const void *addr, size_t length, int prot, int flags,
+off_t offset) = 0;
+enum Kind {
+MAPPABLE_FILE,
+MAPPABLE_EXTRACT_FILE,
+MAPPABLE_DEFLATE,
+MAPPABLE_SEEKABLE_ZSTREAM
+};
+virtual Kind GetKind() const = 0;
+private:
+virtual void munmap(void *addr, size_t length) {
+::munmap(addr, length);
+}
+/* Limit use of Mappable::munmap to classes that keep track of the address
+* and size of the mapping. This allows to ignore ::munmap return value. */
+friend class Mappable1stPagePtr;
+friend class LibHandle;
+public:
+/**
+* Ensures the availability of the memory pages for the page(s) containing
+* the given address. Returns whether the pages were successfully made
+* available.
+*/
+virtual bool ensure(const void *addr) { return true; }
+/**
+* Indicate to a Mappable instance that no further mmap is going to happen.
+*/
+virtual void finalize() = 0;
+/**
+* Shows some stats about the Mappable instance.
+* Meant for MappableSeekableZStream only.
+* As Mappables don't keep track of what they are instanciated for, the name
+* argument is used to make the stats logging useful to the reader. The when
+* argument is to be used by the caller to give an identifier of the when
+* the stats call is made.
+*/
+virtual void stats(const char *when, const char *name) const { }
+/**
+* Returns the maximum length that can be mapped from this Mappable for
+* offset = 0.
+*/
+virtual size_t GetLength() const = 0;
+};
+/**
+* Mappable implementation for plain files
+*/
+class MappableFile: public Mappable
+{
+public:
+~MappableFile() { }
+/**
+* Create a MappableFile instance for the given file path.
+*/
+static Mappable *Create(const char *path);
+/* Inherited from Mappable */
+virtual MemoryRange mmap(const void *addr, size_t length, int prot, int flags, off_t offset);
+virtual void finalize();
+virtual size_t GetLength() const;
+virtual Kind GetKind() const { return MAPPABLE_FILE; };
+protected:
+MappableFile(int fd): fd(fd) { }
+private:
+/* File descriptor */
+AutoCloseFD fd;
+};
+/**
+* Mappable implementation for deflated stream in a Zip archive
+* Inflates the complete stream into a cache file.
+*/
+class MappableExtractFile: public MappableFile
+{
+public:
+~MappableExtractFile();
+/**
+* Create a MappableExtractFile instance for the given Zip stream. The name
+* argument is used to create the cache file in the cache directory.
+*/
+static Mappable *Create(const char *name, Zip *zip, Zip::Stream *stream);
+/* Override finalize from MappableFile */
+virtual void finalize() {}
+virtual Kind GetKind() const { return MAPPABLE_EXTRACT_FILE; };
+private:
+MappableExtractFile(int fd, char *path)
+: MappableFile(fd), path(path), pid(getpid()) { }
+/**
+* AutoUnlinkFile keeps track or a file name and removes (unlinks) the file
+* when the instance is destroyed.
+*/
+struct AutoUnlinkFileTraits: public mozilla::ScopedDeleteArrayTraits<char>
+{
+static void release(char *value)
+{
+if (!value)
+return;
+unlink(value);
+mozilla::ScopedDeleteArrayTraits<char>::release(value);
+}
+};
+typedef mozilla::Scoped<AutoUnlinkFileTraits> AutoUnlinkFile;
+/* Extracted file */
+AutoUnlinkFile path;
+/* Id of the process that initialized the instance */
+pid_t pid;
+};
+class _MappableBuffer;
+/**
+* Mappable implementation for deflated stream in a Zip archive.
+* Inflates the mapped bits in a temporary buffer.
+*/
+class MappableDeflate: public Mappable
+{
+public:
+~MappableDeflate();
+/**
+* Create a MappableDeflate instance for the given Zip stream. The name
+* argument is used for an appropriately named temporary file, and the Zip
+* instance is given for the MappableDeflate to keep a reference of it.
+*/
+static Mappable *Create(const char *name, Zip *zip, Zip::Stream *stream);
+/* Inherited from Mappable */
+virtual MemoryRange mmap(const void *addr, size_t length, int prot, int flags, off_t offset);
+virtual void finalize();
+virtual size_t GetLength() const;
+virtual Kind GetKind() const { return MAPPABLE_DEFLATE; };
+private:
+MappableDeflate(_MappableBuffer *buf, Zip *zip, Zip::Stream *stream);
+/* Zip reference */
+mozilla::RefPtr<Zip> zip;
+/* Decompression buffer */
+mozilla::ScopedDeletePtr<_MappableBuffer> buffer;
+/* Zlib data */
+z_stream zStream;
+};
+/**
+* Mappable implementation for seekable zStreams.
+* Inflates the mapped bits in a temporary buffer, on demand.
+*/
+class MappableSeekableZStream: public Mappable
+{
+public:
+~MappableSeekableZStream();
+/**
+* Create a MappableSeekableZStream instance for the given Zip stream. The
+* name argument is used for an appropriately named temporary file, and the
+* Zip instance is given for the MappableSeekableZStream to keep a reference
+* of it.
+*/
+static Mappable *Create(const char *name, Zip *zip,
+Zip::Stream *stream);
+/* Inherited from Mappable */
+virtual MemoryRange mmap(const void *addr, size_t length, int prot, int flags, off_t offset);
+virtual void munmap(void *addr, size_t length);
+virtual void finalize();
+virtual bool ensure(const void *addr);
+virtual void stats(const char *when, const char *name) const;
+virtual size_t GetLength() const;
+virtual Kind GetKind() const { return MAPPABLE_SEEKABLE_ZSTREAM; };
+private:
+MappableSeekableZStream(Zip *zip);
+/* Zip reference */
+mozilla::RefPtr<Zip> zip;
+/* Decompression buffer */
+mozilla::ScopedDeletePtr<_MappableBuffer> buffer;
+/* Seekable ZStream */
+SeekableZStream zStream;
+/* Keep track of mappings performed with MappableSeekableZStream::mmap so
+* that they can be realized by MappableSeekableZStream::ensure.
+* Values stored in the struct are those passed to mmap */
+struct LazyMap
+{
+const void *addr;
+size_t length;
+int prot;
+off_t offset;
+/* Returns addr + length, as a pointer */
+const void *end() const {
+return reinterpret_cast<const void *>
+(reinterpret_cast<const unsigned char *>(addr) + length);
+}
+/* Returns offset + length */
+const off_t endOffset() const {
+return offset + length;
+}
+/* Returns the offset corresponding to the given address */
+const off_t offsetOf(const void *ptr) const {
+return reinterpret_cast<uintptr_t>(ptr)
+- reinterpret_cast<uintptr_t>(addr) + offset;
+}
+/* Returns whether the given address is in the LazyMap range */
+const bool Contains(const void *ptr) const {
+return (ptr >= addr) && (ptr < end());
+}
+};
+/* List of all mappings */
+std::vector<LazyMap> lazyMaps;
+/* Array keeping track of which chunks have already been decompressed.
+* Each value is the number of pages decompressed for the given chunk. */
+mozilla::ScopedDeleteArray<unsigned char> chunkAvail;
+/* Number of chunks that have already been decompressed. */
+mozilla::Atomic<size_t> chunkAvailNum;
+/* Mutex protecting decompression */
+pthread_mutex_t mutex;
+};
+#endif /* Mappable_h */

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comparison: mozglue/linker/Mappable.h

mozglue/linker/Mappable.h