Adding upstream version 124.0.1.upstream/124.0.1

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

1 files changed, 195 insertions, 0 deletions

diff --git a/toolkit/components/uniffi-bindgen-gecko-js/src/templates/js/CallbackInterfaceRuntime.sys.mjs b/toolkit/components/uniffi-bindgen-gecko-js/src/templates/js/CallbackInterfaceRuntime.sys.mjs
new file mode 100644
index 0000000000..a4d88136ab
--- /dev/null
+++ b/toolkit/components/uniffi-bindgen-gecko-js/src/templates/js/CallbackInterfaceRuntime.sys.mjs
@@ -0,0 +1,195 @@
+
+/**
+ * Handler for a single UniFFI CallbackInterface
+ *
+ * This class stores objects that implement a callback interface in a handle
+ * map, allowing them to be referenced by the Rust code using an integer
+ * handle.
+ *
+ * While the callback object is stored in the map, it allows the Rust code to
+ * call methods on the object using the callback object handle, a method id,
+ * and an ArrayBuffer packed with the method arguments.
+ *
+ * When the Rust code drops its reference, it sends a call with the methodId=0,
+ * which causes callback object to be removed from the map.
+ */
+class UniFFICallbackHandler {
+    #name;
+    #interfaceId;
+    #handleCounter;
+    #handleMap;
+    #methodHandlers;
+    #allowNewCallbacks
+
+    /**
+     * Create a UniFFICallbackHandler
+     * @param {string} name - Human-friendly name for this callback interface
+     * @param {int} interfaceId - Interface ID for this CallbackInterface.
+     * @param {UniFFICallbackMethodHandler[]} methodHandlers -- UniFFICallbackHandler for each method, in the same order as the UDL file
+     */
+     constructor(name, interfaceId, methodHandlers) {
+        this.#name = name;
+        this.#interfaceId = interfaceId;
+        this.#handleCounter = 0;
+        this.#handleMap = new Map();
+        this.#methodHandlers = methodHandlers;
+        this.#allowNewCallbacks = true;
+
+        UniFFIScaffolding.registerCallbackHandler(this.#interfaceId, this.invokeCallback.bind(this));
+        Services.obs.addObserver(this, "xpcom-shutdown");
+     }
+
+    /**
+     * Store a callback object in the handle map and return the handle
+     *
+     * @param {obj} callbackObj - Object that implements the callback interface
+     * @returns {int} - Handle for this callback object, this is what gets passed back to Rust.
+     */
+    storeCallbackObj(callbackObj) {
+        if (!this.#allowNewCallbacks) {
+            throw new UniFFIError(`No new callbacks allowed for ${this.#name}`);
+        }
+        const handle = this.#handleCounter;
+        this.#handleCounter += 1;
+        this.#handleMap.set(handle, new UniFFICallbackHandleMapEntry(callbackObj, Components.stack.caller.formattedStack.trim()));
+        return handle;
+    }
+
+    /**
+     * Get a previously stored callback object
+     *
+     * @param {int} handle - Callback object handle, returned from `storeCallbackObj()`
+     * @returns {obj} - Callback object
+     */
+    getCallbackObj(handle) {
+        return this.#handleMap.get(handle).callbackObj;
+    }
+
+    /**
+     * Set if new callbacks are allowed for this handler
+     *
+     * This is called with false during shutdown to ensure the callback maps don't
+     * prevent JS objects from being GCed.
+     */
+    setAllowNewCallbacks(allow) {
+        this.#allowNewCallbacks = allow
+    }
+
+    /**
+     * Check that no callbacks are currently registered
+     *
+     * If there are callbacks registered a UniFFIError will be thrown.  This is
+     * called during shutdown to generate an alert if there are leaked callback
+     * interfaces.
+     */
+    assertNoRegisteredCallbacks() {
+        if (this.#handleMap.size > 0) {
+            const entry = this.#handleMap.values().next().value;
+            throw new UniFFIError(`UniFFI interface ${this.#name} has ${this.#handleMap.size} registered callbacks at xpcom-shutdown. This likely indicates a UniFFI callback leak.\nStack trace for the first leaked callback:\n${entry.stackTrace}.`);
+        }
+    }
+
+    /**
+     * Invoke a method on a stored callback object
+     * @param {int} handle - Object handle
+     * @param {int} methodId - Method identifier.  This the 1-based index of
+     *   the method from the UDL file.  0 is the special drop method, which
+     *   removes the callback object from the handle map.
+     * @param {ArrayBuffer} argsArrayBuffer - Arguments to pass to the method, packed in an ArrayBuffer
+     */
+    invokeCallback(handle, methodId, argsArrayBuffer) {
+        try {
+            this.#invokeCallbackInner(handle, methodId, argsArrayBuffer);
+        } catch (e) {
+            console.error(`internal error invoking callback: ${e}`)
+        }
+    }
+
+    #invokeCallbackInner(handle, methodId, argsArrayBuffer) {
+        const callbackObj = this.getCallbackObj(handle);
+        if (callbackObj === undefined) {
+            throw new UniFFIError(`${this.#name}: invalid callback handle id: ${handle}`);
+        }
+
+        // Special-cased drop method, remove the object from the handle map and
+        // return an empty array buffer
+        if (methodId == 0) {
+            this.#handleMap.delete(handle);
+            return;
+        }
+
+        // Get the method data, converting from 1-based indexing
+        const methodHandler = this.#methodHandlers[methodId - 1];
+        if (methodHandler === undefined) {
+            throw new UniFFIError(`${this.#name}: invalid method id: ${methodId}`)
+        }
+
+        methodHandler.call(callbackObj, argsArrayBuffer);
+    }
+
+    /**
+     * xpcom-shutdown observer method
+     *
+     * This handles:
+     *  - Deregistering ourselves as the UniFFI callback handler
+     *  - Checks for any leftover stored callbacks which indicate memory leaks
+     */
+    observe(aSubject, aTopic, aData) {
+        if (aTopic == "xpcom-shutdown") {
+            try {
+                this.setAllowNewCallbacks(false);
+                this.assertNoRegisteredCallbacks();
+                UniFFIScaffolding.deregisterCallbackHandler(this.#interfaceId);
+            } catch (ex) {
+                console.error(`UniFFI Callback interface error during xpcom-shutdown: ${ex}`);
+                Cc["@mozilla.org/xpcom/debug;1"]
+                    .getService(Ci.nsIDebug2)
+                    .abort(ex.filename, ex.lineNumber);
+            }
+         }
+    }
+}
+
+/**
+ * Handles calling a single method for a callback interface
+ */
+class UniFFICallbackMethodHandler {
+    #name;
+    #argsConverters;
+
+    /**
+     * Create a UniFFICallbackMethodHandler
+
+     * @param {string} name -- Name of the method to call on the callback object
+     * @param {FfiConverter[]} argsConverters - FfiConverter for each argument type
+     */
+    constructor(name, argsConverters) {
+        this.#name = name;
+        this.#argsConverters = argsConverters;
+    }
+
+    /**
+     * Invoke the method
+     *
+     * @param {obj} callbackObj -- Object implementing the callback interface for this method
+     * @param {ArrayBuffer} argsArrayBuffer -- Arguments for the method, packed in an ArrayBuffer
+     */
+     call(callbackObj, argsArrayBuffer) {
+        const argsStream = new ArrayBufferDataStream(argsArrayBuffer);
+        const args = this.#argsConverters.map(converter => converter.read(argsStream));
+        callbackObj[this.#name](...args);
+    }
+}
+
+/**
+ * UniFFICallbackHandler.handleMap entry
+ *
+ * @property callbackObj - Callback object, this must implement the callback interface.
+ * @property {string} stackTrace - Stack trace from when the callback object was registered.  This is used to proved extra context when debugging leaked callback objects.
+ */
+class UniFFICallbackHandleMapEntry {
+    constructor(callbackObj, stackTrace) {
+        this.callbackObj = callbackObj;
+        this.stackTrace = stackTrace
+    }
+}