Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 300 insertions, 0 deletions

diff --git a/js/public/ArrayBuffer.h b/js/public/ArrayBuffer.h
new file mode 100644
index 0000000000..b4911c819e
--- /dev/null
+++ b/js/public/ArrayBuffer.h
@@ -0,0 +1,300 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+/* ArrayBuffer functionality. */
+
+#ifndef js_ArrayBuffer_h
+#define js_ArrayBuffer_h
+
+#include <stddef.h>  // size_t
+#include <stdint.h>  // uint32_t
+
+#include "jstypes.h"  // JS_PUBLIC_API
+#include "js/TypeDecls.h"
+
+struct JS_PUBLIC_API JSContext;
+class JS_PUBLIC_API JSObject;
+
+namespace JS {
+
+class JS_PUBLIC_API AutoRequireNoGC;
+
+// CREATION
+
+/**
+ * Create a new ArrayBuffer with the given byte length.
+ */
+extern JS_PUBLIC_API JSObject* NewArrayBuffer(JSContext* cx, size_t nbytes);
+
+/**
+ * Create a new ArrayBuffer with the given |contents|, which may be null only
+ * if |nbytes == 0|.  |contents| must be allocated compatible with deallocation
+ * by |JS_free|.
+ *
+ * If and only if an ArrayBuffer is successfully created and returned,
+ * ownership of |contents| is transferred to the new ArrayBuffer.
+ *
+ * Care must be taken that |nbytes| bytes of |content| remain valid for the
+ * duration of this call.  In particular, passing the length/pointer of existing
+ * typed array or ArrayBuffer data is generally unsafe: if a GC occurs during a
+ * call to this function, it could move those contents to a different location
+ * and invalidate the provided pointer.
+ */
+extern JS_PUBLIC_API JSObject* NewArrayBufferWithContents(JSContext* cx,
+                                                          size_t nbytes,
+                                                          void* contents);
+
+/**
+ * Create a new ArrayBuffer, whose bytes are set to the values of the bytes in
+ * the provided ArrayBuffer.
+ *
+ * |maybeArrayBuffer| is asserted to be non-null.  An error is thrown if
+ * |maybeArrayBuffer| would fail the |IsArrayBufferObject| test given further
+ * below or if |maybeArrayBuffer| is detached.
+ *
+ * |maybeArrayBuffer| may store its contents in any fashion (i.e. it doesn't
+ * matter whether |maybeArrayBuffer| was allocated using |JS::NewArrayBuffer|,
+ * |JS::NewExternalArrayBuffer|, or any other ArrayBuffer-allocating function).
+ *
+ * The newly-created ArrayBuffer is effectively creatd as if by
+ * |JS::NewArrayBufferWithContents| passing in |maybeArrayBuffer|'s internal
+ * data pointer and length, in a manner safe against |maybeArrayBuffer|'s data
+ * being moved around by the GC.  In particular, the new ArrayBuffer will not
+ * behave like one created for WASM or asm.js, so it *can* be detached.
+ */
+extern JS_PUBLIC_API JSObject* CopyArrayBuffer(
+    JSContext* cx, JS::Handle<JSObject*> maybeArrayBuffer);
+
+using BufferContentsFreeFunc = void (*)(void* contents, void* userData);
+
+/**
+ * Create a new ArrayBuffer with the given contents. The contents must not be
+ * modified by any other code, internal or external.
+ *
+ * When the ArrayBuffer is ready to be disposed of, `freeFunc(contents,
+ * freeUserData)` will be called to release the ArrayBuffer's reference on the
+ * contents.
+ *
+ * `freeFunc()` must not call any JSAPI functions that could cause a garbage
+ * collection.
+ *
+ * The caller must keep the buffer alive until `freeFunc()` is called, or, if
+ * `freeFunc` is null, until the JSRuntime is destroyed.
+ *
+ * The caller must not access the buffer on other threads. The JS engine will
+ * not allow the buffer to be transferred to other threads. If you try to
+ * transfer an external ArrayBuffer to another thread, the data is copied to a
+ * new malloc buffer. `freeFunc()` must be threadsafe, and may be called from
+ * any thread.
+ *
+ * This allows ArrayBuffers to be used with embedder objects that use reference
+ * counting, for example. In that case the caller is responsible
+ * for incrementing the reference count before passing the contents to this
+ * function. This also allows using non-reference-counted contents that must be
+ * freed with some function other than free().
+ */
+extern JS_PUBLIC_API JSObject* NewExternalArrayBuffer(
+    JSContext* cx, size_t nbytes, void* contents,
+    BufferContentsFreeFunc freeFunc, void* freeUserData = nullptr);
+
+/**
+ * Create a new ArrayBuffer with the given non-null |contents|.
+ *
+ * Ownership of |contents| remains with the caller: it isn't transferred to the
+ * returned ArrayBuffer.  Callers of this function *must* ensure that they
+ * perform these two steps, in this order, to properly relinquish ownership of
+ * |contents|:
+ *
+ *   1. Call |JS::DetachArrayBuffer| on the buffer returned by this function.
+ *      (|JS::DetachArrayBuffer| is generally fallible, but a call under these
+ *      circumstances is guaranteed to succeed.)
+ *   2. |contents| may be deallocated or discarded consistent with the manner
+ *      in which it was allocated.
+ *
+ * Do not simply allow the returned buffer to be garbage-collected before
+ * deallocating |contents|, because in general there is no way to know *when*
+ * an object is fully garbage-collected to the point where this would be safe.
+ */
+extern JS_PUBLIC_API JSObject* NewArrayBufferWithUserOwnedContents(
+    JSContext* cx, size_t nbytes, void* contents);
+
+/**
+ * Create a new mapped ArrayBuffer with the given memory mapped contents. It
+ * must be legal to free the contents pointer by unmapping it. On success,
+ * ownership is transferred to the new mapped ArrayBuffer.
+ */
+extern JS_PUBLIC_API JSObject* NewMappedArrayBufferWithContents(JSContext* cx,
+                                                                size_t nbytes,
+                                                                void* contents);
+
+/**
+ * Create memory mapped ArrayBuffer contents.
+ * Caller must take care of closing fd after calling this function.
+ */
+extern JS_PUBLIC_API void* CreateMappedArrayBufferContents(int fd,
+                                                           size_t offset,
+                                                           size_t length);
+
+/**
+ * Release the allocated resource of mapped ArrayBuffer contents before the
+ * object is created.
+ * If a new object has been created by JS::NewMappedArrayBufferWithContents()
+ * with this content, then JS::DetachArrayBuffer() should be used instead to
+ * release the resource used by the object.
+ */
+extern JS_PUBLIC_API void ReleaseMappedArrayBufferContents(void* contents,
+                                                           size_t length);
+
+// TYPE TESTING
+
+/*
+ * Check whether obj supports the JS::GetArrayBuffer* APIs.  Note that this may
+ * return false if a security wrapper is encountered that denies the unwrapping.
+ * If this test succeeds, then it is safe to call the various predicate and
+ * accessor JSAPI calls defined below.
+ */
+extern JS_PUBLIC_API bool IsArrayBufferObject(JSObject* obj);
+
+// PREDICATES
+
+/**
+ * Check whether the obj is a detached ArrayBufferObject. Note that this may
+ * return false if a security wrapper is encountered that denies the
+ * unwrapping.
+ */
+extern JS_PUBLIC_API bool IsDetachedArrayBufferObject(JSObject* obj);
+
+/**
+ * Check whether the obj is ArrayBufferObject and memory mapped. Note that this
+ * may return false if a security wrapper is encountered that denies the
+ * unwrapping.
+ */
+extern JS_PUBLIC_API bool IsMappedArrayBufferObject(JSObject* obj);
+
+/**
+ * Return true if the ArrayBuffer |obj| contains any data, i.e. it is not a
+ * detached ArrayBuffer.  (ArrayBuffer.prototype is not an ArrayBuffer.)
+ *
+ * |obj| must have passed a JS::IsArrayBufferObject test, or somehow be known
+ * that it would pass such a test: it is an ArrayBuffer or a wrapper of an
+ * ArrayBuffer, and the unwrapping will succeed.
+ */
+extern JS_PUBLIC_API bool ArrayBufferHasData(JSObject* obj);
+
+// ACCESSORS
+
+extern JS_PUBLIC_API JSObject* UnwrapArrayBuffer(JSObject* obj);
+
+/**
+ * Attempt to unwrap |obj| as an ArrayBuffer.
+ *
+ * If |obj| *is* an ArrayBuffer, return it unwrapped and set |*length| and
+ * |*data| to weakly refer to the ArrayBuffer's contents.
+ *
+ * If |obj| isn't an ArrayBuffer, return nullptr and do not modify |*length| or
+ * |*data|.
+ */
+extern JS_PUBLIC_API JSObject* GetObjectAsArrayBuffer(JSObject* obj,
+                                                      size_t* length,
+                                                      uint8_t** data);
+
+/**
+ * Return the available byte length of an ArrayBuffer.
+ *
+ * |obj| must have passed a JS::IsArrayBufferObject test, or somehow be known
+ * that it would pass such a test: it is an ArrayBuffer or a wrapper of an
+ * ArrayBuffer, and the unwrapping will succeed.
+ */
+extern JS_PUBLIC_API size_t GetArrayBufferByteLength(JSObject* obj);
+
+// This one isn't inlined because there are a bunch of different ArrayBuffer
+// classes that would have to be individually handled here.
+//
+// There is an isShared out argument for API consistency (eases use from DOM).
+// It will always be set to false.
+extern JS_PUBLIC_API void GetArrayBufferLengthAndData(JSObject* obj,
+                                                      size_t* length,
+                                                      bool* isSharedMemory,
+                                                      uint8_t** data);
+
+/**
+ * Return a pointer to the start of the data referenced by a typed array. The
+ * data is still owned by the typed array, and should not be modified on
+ * another thread. Furthermore, the pointer can become invalid on GC (if the
+ * data is small and fits inside the array's GC header), so callers must take
+ * care not to hold on across anything that could GC.
+ *
+ * |obj| must have passed a JS::IsArrayBufferObject test, or somehow be known
+ * that it would pass such a test: it is an ArrayBuffer or a wrapper of an
+ * ArrayBuffer, and the unwrapping will succeed.
+ *
+ * |*isSharedMemory| is always set to false.  The argument is present to
+ * simplify its use from code that also interacts with SharedArrayBuffer.
+ */
+extern JS_PUBLIC_API uint8_t* GetArrayBufferData(JSObject* obj,
+                                                 bool* isSharedMemory,
+                                                 const AutoRequireNoGC&);
+
+// MUTATORS
+
+/**
+ * Detach an ArrayBuffer, causing all associated views to no longer refer to
+ * the ArrayBuffer's original attached memory.
+ *
+ * This function throws only if it is provided a non-ArrayBuffer object or if
+ * the provided ArrayBuffer is a WASM-backed ArrayBuffer or an ArrayBuffer used
+ * in asm.js code.
+ */
+extern JS_PUBLIC_API bool DetachArrayBuffer(JSContext* cx,
+                                            Handle<JSObject*> obj);
+
+// Indicates if an object has a defined [[ArrayBufferDetachKey]] internal slot,
+// which indicates an ArrayBuffer cannot be detached
+extern JS_PUBLIC_API bool HasDefinedArrayBufferDetachKey(JSContext* cx,
+                                                         Handle<JSObject*> obj,
+                                                         bool* isDefined);
+
+/**
+ * Steal the contents of the given ArrayBuffer. The ArrayBuffer has its length
+ * set to 0 and its contents array cleared. The caller takes ownership of the
+ * return value and must free it or transfer ownership via
+ * JS::NewArrayBufferWithContents when done using it.
+ */
+extern JS_PUBLIC_API void* StealArrayBufferContents(JSContext* cx,
+                                                    Handle<JSObject*> obj);
+
+/**
+ * Copy data from one array buffer to another.
+ *
+ * Both fromBuffer and toBuffer must be (possibly wrapped)
+ * ArrayBufferObjectMaybeShared.
+ *
+ * This method may throw if the sizes don't match, or if unwrapping fails.
+ *
+ * The API for this is modelled on CopyDataBlockBytes from the spec:
+ * https://tc39.es/ecma262/#sec-copydatablockbytes
+ */
+[[nodiscard]] extern JS_PUBLIC_API bool ArrayBufferCopyData(
+    JSContext* cx, Handle<JSObject*> toBlock, size_t toIndex,
+    Handle<JSObject*> fromBlock, size_t fromIndex, size_t count);
+
+/**
+ * Copy data from one array buffer to another.
+ *
+ * srcBuffer must be a (possibly wrapped) ArrayBufferObjectMaybeShared.
+ *
+ * This method may throw if unwrapping or allocation fails.
+ *
+ * The API for this is modelled on CloneArrayBuffer from the spec:
+ * https://tc39.es/ecma262/#sec-clonearraybuffer
+ */
+extern JS_PUBLIC_API JSObject* ArrayBufferClone(JSContext* cx,
+                                                Handle<JSObject*> srcBuffer,
+                                                size_t srcByteOffset,
+                                                size_t srcLength);
+
+}  // namespace JS
+
+#endif /* js_ArrayBuffer_h */