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// Copyright (c) 2017-2022 Cloudflare, Inc.
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// Licensed under the Apache 2.0 license found in the LICENSE file or at:
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//     https://opensource.org/licenses/Apache-2.0
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#pragma once
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#include <v8-script.h>
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#include <kj/map.h>
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#include <kj/mutex.h>
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#include <kj/string.h>
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namespace workerd::jsg {
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// The CompileCache is used to hold cached compilation data for built-in JavaScript modules.
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//
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// Importantly, this is a process-lifetime in-memory cache that is only appropriate for
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// built-in modules.
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//
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// The memory-safety of this cache depends on the assumption that entries are never removed
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// or replaced. If things are ever changed such that entries are removed/replaced, then
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// we'd likely need to have find return an atomic refcount or something similar.
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class CompileCache {
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 public:
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  class Data {
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   public:
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    Data(): data(nullptr), length(0), owningPtr(nullptr) {};
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    explicit Data(std::shared_ptr<v8::ScriptCompiler::CachedData> cached_data)
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        : data(cached_data->data),
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          length(cached_data->length),
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          owningPtr(cached_data) {};
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    // Returns a v8::ScriptCompiler::CachedData corresponding to this
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    // CompileCache::Data. The lifetime of the returned
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    // v8::ScriptCompiler::CachedData must not outlive that of the data.
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    std::unique_ptr<v8::ScriptCompiler::CachedData> AsCachedData();
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    const uint8_t* data;
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    size_t length;
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   private:
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    std::shared_ptr<void> owningPtr;
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  };
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  void add(kj::StringPtr key, std::shared_ptr<v8::ScriptCompiler::CachedData> cached) const;
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  kj::Maybe<Data&> find(kj::StringPtr key) const;
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  static const CompileCache& get() {
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    static const CompileCache instance;
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    return instance;
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  }
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 private:
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  // The key is the address of the static global that was compiled to produce the CachedData.
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  kj::MutexGuarded<kj::HashMap<kj::String, Data>> cache;
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};
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}  // namespace workerd::jsg