8132953: imageDecompressor.hpp should not include precompiled.hpp
Reviewed-by: dholmes
/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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*/
#ifndef SHARE_VM_CLASSFILE_IMAGEDECOMPRESSOR_HPP
#define SHARE_VM_CLASSFILE_IMAGEDECOMPRESSOR_HPP
#include "runtime/thread.inline.hpp"
#include "classfile/classLoader.hpp"
#include "classfile/imageFile.hpp"
#include "classfile/symbolTable.hpp"
#include "oops/symbol.hpp"
#include "utilities/growableArray.hpp"
/*
* Compressed resources located in image have an header.
* This header contains:
* - _magic: A magic u4, required to retrieved the header in the compressed content
* - _size: The size of the compressed resource.
* - _uncompressed_size: The uncompressed size of the compressed resource.
* - _decompressor_name_offset: The ImageDecompressor instance name StringsTable offset.
* - _decompressor_config_offset: StringsTable offset of configuration that could be needed by
* the decompressor in order to decompress.
* - _is_terminal: 1: the compressed content is terminal. Uncompressing it would
* create the actual resource. 0: the compressed content is not terminal. Uncompressing it
* will result in a compressed content to be decompressed (This occurs when a stack of compressors
* have been used to compress the resource.
*/
struct ResourceHeader {
/* Length of header, needed to retrieve content offset */
static const u1 resource_header_length = 21;
/* magic bytes that identifies a compressed resource header*/
static const u4 resource_header_magic = 0xCAFEFAFA;
u4 _magic; // Resource header
u4 _size; // Resource size
u4 _uncompressed_size; // Expected uncompressed size
u4 _decompressor_name_offset; // Strings table decompressor offset
u4 _decompressor_config_offset; // Strings table config offset
u1 _is_terminal; // Last decompressor 1, otherwise 0.
};
/*
* Resources located in jimage file can be compressed. Compression occurs at
* jimage file creation time. When compressed a resource is added an header that
* contains the name of the compressor that compressed it.
* Various compression strategies can be applied to compress a resource.
* The same resource can even be compressed multiple time by a stack of compressors.
* At runtime, a resource is decompressed in a loop until there is no more header
* meaning that the resource is equivalent to the not compressed resource.
* In each iteration, the name of the compressor located in the current header
* is used to retrieve the associated instance of ImageDecompressor.
* For example “zip” is the name of the compressor that compresses resources
* using the zip algorithm. The ZipDecompressor class name is also “zip”.
* ImageDecompressor instances are retrieved from a static array in which
* they are registered.
*/
class ImageDecompressor: public CHeapObj<mtClass> {
private:
const Symbol* _name;
/*
* Array of concrete decompressors. This array is used to retrieve the decompressor
* that can handle resource decompression.
*/
static GrowableArray<ImageDecompressor*>* _decompressors;
/*
* Identifier of a decompressor. This name is the identification key to retrieve
* decompressor from a resource header.
*/
inline const Symbol* get_name() const { return _name; }
protected:
ImageDecompressor(const Symbol* name) : _name(name) {
}
virtual void decompress_resource(u1* data, u1* uncompressed,
ResourceHeader* header, const ImageStrings* strings) = 0;
public:
inline static void add_decompressor(ImageDecompressor* decompressor) {
_decompressors->append(decompressor);
}
inline static ImageDecompressor* get_decompressor(const char * decompressor_name) {
Thread* THREAD = Thread::current();
TempNewSymbol sym = SymbolTable::new_symbol(decompressor_name,
(int) strlen(decompressor_name), CHECK_NULL);
if (HAS_PENDING_EXCEPTION) {
warning("can't create symbol\n");
CLEAR_PENDING_EXCEPTION;
return NULL;
}
for (int i = 0; i < _decompressors->length(); i++) {
ImageDecompressor* decompressor = _decompressors->at(i);
if (decompressor->get_name()->fast_compare(sym) == 0) {
return decompressor;
}
}
guarantee(false, "No decompressor found.");
return NULL;
}
static void decompress_resource(u1* compressed, u1* uncompressed,
u4 uncompressed_size, const ImageStrings* strings, bool is_C_heap);
};
/**
* Zip decompressor.
*/
class ZipDecompressor : public ImageDecompressor {
public:
ZipDecompressor(const Symbol* sym) : ImageDecompressor(sym) { }
void decompress_resource(u1* data, u1* uncompressed, ResourceHeader* header,
const ImageStrings* strings);
};
#endif // SHARE_VM_CLASSFILE_IMAGEDECOMPRESSOR_HPP