xpcom/io/nsIBinaryInputStream.idl
author Jan Henning <jh+bugzilla@buttercookie.de>
Thu, 07 Feb 2019 20:41:16 +0000
changeset 512996 95b884dcbd6f001b990a6353980280050fab9ac6
parent 204102 e700f9da758571e3e39063ee9d74e63e226353bb
child 534859 020c8c871c0d3b3920fe95935cfef06501976c0f
permissions -rw-r--r--
Bug 1496684 - Dispatch commonly expected startup notifications when opening a GeckoView window. r=snorp a=lizzard Once a webextension using a blocking WebRequest listener has started loading, all network connections covered by the extension's manifest are held until the extension is ready the process them. One condition for the extension being ready apparently includes browser startup having progressed far enough, as signified by "browser-delayed-startup-finished" having been dispatched. Therefore, we have to start sending that notification when opening a new Gecko- View window, too, and copy Fennec's InitLater() system for that. Unlike Fennec, we cannot tie registration of those InitLater() runnables to the initial content load having progressed far enough because of a) e10s, which makes that approach neither easily possible nor really sensible, as content will load in a different process in that case, and b) because we're racing with extension startup here - if extensions are loaded quick enough to block even the initial page load, we'd be deadlocked: We cannot send the notification until the page finishes loading, but the page cannot load until we send the notification. Fennec isn't affected by the latter problem because "sessionstore-windows-restored", which Fennec will send in any case, serves as an alternative pathway for completing extension startup. And unlike Desktop, we don't really have any chrome content to paint, so we cannot tie delayed initialisation to a paint listener for that, either. Therefore, we simply fire off a runnable at the *end* of geckoview.js's startup() method, which should give more pressing initialisation tasks enough of a headstart. For completeness, we're also adding the "browser-idle-startup-tasks-finished" notification and thereby solve bug 1465832 as well, allowing the ScriptPreloader to detect which scripts are commonly loaded during GeckoView startup and to start caching and pre-parsing them. Differential Revision: https://phabricator.services.mozilla.com/D18865

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * 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/. */

#include "nsIInputStream.idl"

/**
 * This interface allows consumption of primitive data types from a "binary
 * stream" containing untagged, big-endian binary data, i.e. as produced by an
 * implementation of nsIBinaryOutputStream.  This might be used, for example,
 * to implement network protocols or to read from architecture-neutral disk
 * files, i.e. ones that can be read and written by both big-endian and
 * little-endian platforms.
 *
 * @See nsIBinaryOutputStream
 */

[scriptable, uuid(899b826b-2eb3-469c-8b31-4c29f5d341a6)]
interface nsIBinaryInputStream : nsIInputStream {
    void setInputStream(in nsIInputStream aInputStream);
    
    /**
     * Read 8-bits from the stream.
     *
     * @return that byte to be treated as a boolean.
     */
    boolean readBoolean();

    uint8_t read8();
    uint16_t read16();
    uint32_t read32();
    uint64_t read64();

    float readFloat();
    double readDouble();

    /**
     * Read an 8-bit pascal style string from the stream.
     * 32-bit length field, followed by length 8-bit chars.
     */
    ACString readCString();

    /**
     * Read an 16-bit pascal style string from the stream.
     * 32-bit length field, followed by length PRUnichars.
     */
    AString readString();

    /**
     * Read an opaque byte array from the stream.
     *
     * @param aLength the number of bytes that must be read.
     *
     * @throws NS_ERROR_FAILURE if it can't read aLength bytes
     */
    void readBytes(in uint32_t aLength,
                   [size_is(aLength), retval] out string aString);

    /**
     * Read an opaque byte array from the stream, storing the results
     * as an array of PRUint8s.
     *
     * @param aLength the number of bytes that must be read.
     *
     * @throws NS_ERROR_FAILURE if it can't read aLength bytes
     */
    void readByteArray(in uint32_t aLength,
                       [array, size_is(aLength), retval] out uint8_t aBytes);

    /**
     * Read opaque bytes from the stream, storing the results in an ArrayBuffer.
     *
     * @param aLength the number of bytes that must be read
     * @param aArrayBuffer the arraybuffer in which to store the results
     * Note: passing view.buffer, where view is an ArrayBufferView of an
     *       ArrayBuffer, is not valid unless view.byteOffset == 0.
     *
     * @return The number of bytes actually read into aArrayBuffer.
     */
    [implicit_jscontext]
    unsigned long readArrayBuffer(in uint32_t aLength, in jsval aArrayBuffer);
};

%{C++

#ifdef MOZILLA_INTERNAL_API
#include "nsString.h"

inline nsresult
NS_ReadOptionalCString(nsIBinaryInputStream* aStream, nsACString& aResult)
{
    bool nonnull;
    nsresult rv = aStream->ReadBoolean(&nonnull);
    if (NS_SUCCEEDED(rv)) {
        if (nonnull)
            rv = aStream->ReadCString(aResult);
        else
            aResult.Truncate();
    }
    return rv;
}

inline nsresult
NS_ReadOptionalString(nsIBinaryInputStream* aStream, nsAString& aResult)
{
    bool nonnull;
    nsresult rv = aStream->ReadBoolean(&nonnull);
    if (NS_SUCCEEDED(rv)) {
        if (nonnull)
            rv = aStream->ReadString(aResult);
        else
            aResult.Truncate();
    }
    return rv;
}
#endif

%}