Common: Add GL Shader Cache class

src/common/gl/shader_cache.h

@@ -0,0 +1,82 @@
+#pragma once
+#include "../hash_combine.h"
+#include "../types.h"
+#include "program.h"
+#include <cstdio>
+#include <functional>
+#include <optional>
+#include <string_view>
+#include <unordered_map>
+#include <vector>
+
+namespace GL {
+
+class ShaderCache
+{
+public:
+  using PreLinkCallback = std::function<void(Program&)>;
+
+  ShaderCache();
+  ~ShaderCache();
+
+  void Open(bool is_gles, std::string_view base_path);
+
+  std::optional<Program> GetProgram(const std::string_view vertex_shader, const std::string_view fragment_shader,
+                                    const PreLinkCallback& callback = {});
+
+private:
+  static constexpr u32 FILE_VERSION = 1;
+
+  struct CacheIndexKey
+  {
+    u64 vertex_source_hash_low;
+    u64 vertex_source_hash_high;
+    u32 vertex_source_length;
+    u64 fragment_source_hash_low;
+    u64 fragment_source_hash_high;
+    u32 fragment_source_length;
+
+    bool operator==(const CacheIndexKey& key) const;
+    bool operator!=(const CacheIndexKey& key) const;
+  };
+
+  struct CacheIndexEntryHasher
+  {
+    std::size_t operator()(const CacheIndexKey& e) const noexcept
+    {
+      std::size_t h = 0;
+      hash_combine(h, e.vertex_source_hash_low, e.vertex_source_hash_high, e.vertex_source_length,
+                   e.fragment_source_hash_low, e.fragment_source_hash_high, e.fragment_source_length);
+      return h;
+    }
+  };
+
+  struct CacheIndexData
+  {
+    u32 file_offset;
+    u32 blob_size;
+    u32 blob_format;
+  };
+
+  using CacheIndex = std::unordered_map<CacheIndexKey, CacheIndexData, CacheIndexEntryHasher>;
+
+  static std::string GetCacheBaseFileName(const std::string_view& base_path);
+  static CacheIndexKey GetCacheKey(const std::string_view& vertex_shader, const std::string_view& fragment_shader);
+
+  bool CreateNew(const std::string& index_filename, const std::string& blob_filename);
+  bool ReadExisting(const std::string& index_filename, const std::string& blob_filename);
+  void Close();
+
+  std::optional<Program> CompileProgram(const std::string_view& vertex_shader, const std::string_view& fragment_shader,
+                                        const PreLinkCallback& callback, bool set_retrievable);
+  std::optional<Program> CompileAndAddProgram(const CacheIndexKey& key, const std::string_view& vertex_shader,
+                                              const std::string_view& fragment_shader, const PreLinkCallback& callback);
+
+  std::FILE* m_index_file = nullptr;
+  std::FILE* m_blob_file = nullptr;
+
+  CacheIndex m_index;
+  bool m_program_binary_supported = false;
+};
+
+} // namespace GL