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// slang-shader-cache-index.h
#pragma once
#include "../../slang.h"
#include "../../slang-gfx.h"
#include "../../slang-com-ptr.h"
#include "../../source/core/slang-string.h"
#include "../../source/core/slang-dictionary.h"
#include "../../source/core/slang-linked-list.h"
#include "../../source/core/slang-stream.h"
#include "../../source/core/slang-crypto.h"
namespace gfx
{
using namespace Slang;
using DigestType = MD5::Digest;
struct ShaderCacheEntry
{
DigestType dependencyBasedDigest;
DigestType contentsBasedDigest;
double lastAccessedTime;
bool operator==(const ShaderCacheEntry& rhs)
{
return dependencyBasedDigest == rhs.dependencyBasedDigest
&& contentsBasedDigest == rhs.contentsBasedDigest
&& lastAccessedTime == rhs.lastAccessedTime;
}
uint32_t getHashCode()
{
return dependencyBasedDigest.getHashCode();
}
};
class PersistentShaderCache : public RefObject
{
public:
PersistentShaderCache(const IDevice::ShaderCacheDesc& inDesc);
~PersistentShaderCache();
// Fetch the cache entry corresponding to the provided key. If found, move the entry to
// the front of entries and return the entry and the corresponding compiled code in
// outCompiledCode. Else, return nullptr.
ShaderCacheEntry* findEntry(const DigestType& key, ISlangBlob** outCompiledCode);
// Add an entry to the cache with the provided key and contents hashes. If
// adding an entry causes the cache to exceed size limitations, this will also
// delete the least recently used entry.
void addEntry(const DigestType& dependencyDigest, const DigestType& contentsDigest, ISlangBlob* compiledCode);
// Update the contents hash for the specified entry in the cache and update the
// corresponding file on disk.
void updateEntry(const DigestType& dependencyDigest, const DigestType& contentsDigest, ISlangBlob* updatedCode);
private:
// Load a previous cache index saved to disk. If not found, create a new cache index
// and save it to disk as filename.
void loadCacheFromFile();
// Delete the last entry (the least recently used) from entries, remove its key/value pair
// from keyToEntry, and remove the corresponding file on disk. Returns the index in 'entries'
// of the removed entry so addEntry() can overwrite the corresponding entry in 'entries'
// with the new entry. This should only be called by addEntry() when the cache reaches maximum capacity.
Index deleteLRUEntry();
// Without access to a physical file path, in-memory file systems cannot leverage file streams and
// need to fall back on a different implementation for loading and saving the cache to memory.
void loadCacheFromMemory();
void saveCacheToMemory();
// The shader cache's description.
IDevice::ShaderCacheDesc desc;
// The underlying file system used for the shader cache.
ComPtr<ISlangMutableFileSystem> mutableShaderCacheFileSystem = nullptr;
bool isMemoryFileSystem = false;
// A file stream to the index file opened during cache load. This will only
// exist for a cache that exists on-disk.
FileStream indexStream;
// Dictionary mapping each shader's key to its corresponding node (entry) in the
// linked list 'orderedEntries'.
Dictionary<DigestType, LinkedNode<Index>*> keyToEntry;
// Linked list containing the corresponding indices in 'entries' for entries in the
// shader cache ordered from most to least recently used.
LinkedList<Index> orderedEntries;
// List of entries in the shader cache. This list is not guaranteed to be in order of recency
// as the main and fall back implementations handle outputting to the file differently.
List<ShaderCacheEntry> entries;
};
}
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