/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- * vim: set ts=8 sts=4 et sw=4 tw=99: * 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 js_StructuredClone_h #define js_StructuredClone_h #include "mozilla/NullPtr.h" #include #include "jstypes.h" #include "js/RootingAPI.h" #include "js/TypeDecls.h" #include "js/Value.h" struct JSRuntime; struct JSStructuredCloneReader; struct JSStructuredCloneWriter; // API for the HTML5 internal structured cloning algorithm. namespace JS { enum TransferableOwnership { // Transferable data has not been filled in yet SCTAG_TMO_UNFILLED = 0, // Structured clone buffer does not yet own the data SCTAG_TMO_UNOWNED = 1, // All values at least this large are owned by the clone buffer SCTAG_TMO_FIRST_OWNED = 2, // Data is a pointer that can be freed SCTAG_TMO_ALLOC_DATA = 2, // Data is a SharedArrayBufferObject's buffer SCTAG_TMO_SHARED_BUFFER = 3, // Data is a memory mapped pointer SCTAG_TMO_MAPPED_DATA = 4, // Data is embedding-specific. The engine can free it by calling the // freeTransfer op. The embedding can also use SCTAG_TMO_USER_MIN and // greater, up to 32 bits, to distinguish specific ownership variants. SCTAG_TMO_CUSTOM = 5, SCTAG_TMO_USER_MIN }; } /* namespace JS */ // Read structured data from the reader r. This hook is used to read a value // previously serialized by a call to the WriteStructuredCloneOp hook. // // tag and data are the pair of uint32_t values from the header. The callback // may use the JS_Read* APIs to read any other relevant parts of the object // from the reader r. closure is any value passed to the JS_ReadStructuredClone // function. Return the new object on success, nullptr on error/exception. typedef JSObject *(*ReadStructuredCloneOp)(JSContext *cx, JSStructuredCloneReader *r, uint32_t tag, uint32_t data, void *closure); // Structured data serialization hook. The engine can write primitive values, // Objects, Arrays, Dates, RegExps, TypedArrays, and ArrayBuffers. Any other // type of object requires application support. This callback must first use // the JS_WriteUint32Pair API to write an object header, passing a value // greater than JS_SCTAG_USER to the tag parameter. Then it can use the // JS_Write* APIs to write any other relevant parts of the value v to the // writer w. closure is any value passed to the JS_WriteStructuredCLone function. // // Return true on success, false on error/exception. typedef bool (*WriteStructuredCloneOp)(JSContext *cx, JSStructuredCloneWriter *w, JS::HandleObject obj, void *closure); // This is called when JS_WriteStructuredClone is given an invalid transferable. // To follow HTML5, the application must throw a DATA_CLONE_ERR DOMException // with error set to one of the JS_SCERR_* values. typedef void (*StructuredCloneErrorOp)(JSContext *cx, uint32_t errorid); // This is called when JS_ReadStructuredClone receives a transferable object // not known to the engine. If this hook does not exist or returns false, the // JS engine calls the reportError op if set, otherwise it throws a // DATA_CLONE_ERR DOM Exception. This method is called before any other // callback and must return a non-null object in returnObject on success. typedef bool (*ReadTransferStructuredCloneOp)(JSContext *cx, JSStructuredCloneReader *r, uint32_t tag, void *content, uint64_t extraData, void *closure, JS::MutableHandleObject returnObject); // Called when JS_WriteStructuredClone receives a transferable object not // handled by the engine. If this hook does not exist or returns false, the JS // engine will call the reportError hook or fall back to throwing a // DATA_CLONE_ERR DOM Exception. This method is called before any other // callback. // // tag: indicates what type of transferable this is. Must be greater than // 0xFFFF0201 (value of the internal SCTAG_TRANSFER_MAP_PENDING_ENTRY) // // ownership: see TransferableOwnership, above. Used to communicate any needed // ownership info to the FreeTransferStructuredCloneOp. // // content, extraData: what the ReadTransferStructuredCloneOp will receive // typedef bool (*TransferStructuredCloneOp)(JSContext *cx, JS::Handle obj, void *closure, // Output: uint32_t *tag, JS::TransferableOwnership *ownership, void **content, uint64_t *extraData); // Called when JS_ClearStructuredClone has to free an unknown transferable // object. Note that it should never trigger a garbage collection (and will // assert in a debug build if it does.) typedef void (*FreeTransferStructuredCloneOp)(uint32_t tag, JS::TransferableOwnership ownership, void *content, uint64_t extraData, void *closure); // The maximum supported structured-clone serialization format version. Note // that this does not need to be bumped for Transferable-only changes, since // they are never saved to persistent storage. #define JS_STRUCTURED_CLONE_VERSION 4 struct JSStructuredCloneCallbacks { ReadStructuredCloneOp read; WriteStructuredCloneOp write; StructuredCloneErrorOp reportError; ReadTransferStructuredCloneOp readTransfer; TransferStructuredCloneOp writeTransfer; FreeTransferStructuredCloneOp freeTransfer; }; // Note: if the *data contains transferable objects, it can be read only once. JS_PUBLIC_API(bool) JS_ReadStructuredClone(JSContext *cx, uint64_t *data, size_t nbytes, uint32_t version, JS::MutableHandleValue vp, const JSStructuredCloneCallbacks *optionalCallbacks, void *closure); // Note: On success, the caller is responsible for calling // JS_ClearStructuredClone(*datap, nbytes, optionalCallbacks, closure). JS_PUBLIC_API(bool) JS_WriteStructuredClone(JSContext *cx, JS::HandleValue v, uint64_t **datap, size_t *nbytesp, const JSStructuredCloneCallbacks *optionalCallbacks, void *closure, JS::HandleValue transferable); JS_PUBLIC_API(bool) JS_ClearStructuredClone(uint64_t *data, size_t nbytes, const JSStructuredCloneCallbacks *optionalCallbacks, void *closure); JS_PUBLIC_API(bool) JS_StructuredCloneHasTransferables(const uint64_t *data, size_t nbytes, bool *hasTransferable); JS_PUBLIC_API(bool) JS_StructuredClone(JSContext *cx, JS::HandleValue v, JS::MutableHandleValue vp, const JSStructuredCloneCallbacks *optionalCallbacks, void *closure); // RAII sugar for JS_WriteStructuredClone. class JS_PUBLIC_API(JSAutoStructuredCloneBuffer) { uint64_t *data_; size_t nbytes_; uint32_t version_; const JSStructuredCloneCallbacks *callbacks_; void *closure_; public: JSAutoStructuredCloneBuffer() : data_(nullptr), nbytes_(0), version_(JS_STRUCTURED_CLONE_VERSION), callbacks_(nullptr), closure_(nullptr) {} JSAutoStructuredCloneBuffer(const JSStructuredCloneCallbacks *callbacks, void *closure) : data_(nullptr), nbytes_(0), version_(JS_STRUCTURED_CLONE_VERSION), callbacks_(callbacks), closure_(closure) {} JSAutoStructuredCloneBuffer(JSAutoStructuredCloneBuffer &&other); JSAutoStructuredCloneBuffer &operator=(JSAutoStructuredCloneBuffer &&other); ~JSAutoStructuredCloneBuffer() { clear(); } uint64_t *data() const { return data_; } size_t nbytes() const { return nbytes_; } void clear(); // Copy some memory. It will be automatically freed by the destructor. bool copy(const uint64_t *data, size_t nbytes, uint32_t version=JS_STRUCTURED_CLONE_VERSION); // Adopt some memory. It will be automatically freed by the destructor. // data must have been allocated by the JS engine (e.g., extracted via // JSAutoStructuredCloneBuffer::steal). void adopt(uint64_t *data, size_t nbytes, uint32_t version=JS_STRUCTURED_CLONE_VERSION); // Remove the buffer so that it will not be automatically freed. // After this, the caller is responsible for feeding the memory back to // JSAutoStructuredCloneBuffer::adopt. void steal(uint64_t **datap, size_t *nbytesp, uint32_t *versionp=nullptr); bool read(JSContext *cx, JS::MutableHandleValue vp, const JSStructuredCloneCallbacks *optionalCallbacks=nullptr, void *closure=nullptr); bool write(JSContext *cx, JS::HandleValue v, const JSStructuredCloneCallbacks *optionalCallbacks=nullptr, void *closure=nullptr); bool write(JSContext *cx, JS::HandleValue v, JS::HandleValue transferable, const JSStructuredCloneCallbacks *optionalCallbacks=nullptr, void *closure=nullptr); private: // Copy and assignment are not supported. JSAutoStructuredCloneBuffer(const JSAutoStructuredCloneBuffer &other) MOZ_DELETE; JSAutoStructuredCloneBuffer &operator=(const JSAutoStructuredCloneBuffer &other) MOZ_DELETE; }; // The range of tag values the application may use for its own custom object types. #define JS_SCTAG_USER_MIN ((uint32_t) 0xFFFF8000) #define JS_SCTAG_USER_MAX ((uint32_t) 0xFFFFFFFF) #define JS_SCERR_RECURSION 0 #define JS_SCERR_TRANSFERABLE 1 JS_PUBLIC_API(void) JS_SetStructuredCloneCallbacks(JSRuntime *rt, const JSStructuredCloneCallbacks *callbacks); JS_PUBLIC_API(bool) JS_ReadUint32Pair(JSStructuredCloneReader *r, uint32_t *p1, uint32_t *p2); JS_PUBLIC_API(bool) JS_ReadBytes(JSStructuredCloneReader *r, void *p, size_t len); JS_PUBLIC_API(bool) JS_ReadTypedArray(JSStructuredCloneReader *r, JS::MutableHandleValue vp); JS_PUBLIC_API(bool) JS_WriteUint32Pair(JSStructuredCloneWriter *w, uint32_t tag, uint32_t data); JS_PUBLIC_API(bool) JS_WriteBytes(JSStructuredCloneWriter *w, const void *p, size_t len); JS_PUBLIC_API(bool) JS_WriteTypedArray(JSStructuredCloneWriter *w, JS::HandleValue v); #endif /* js_StructuredClone_h */