[Libreoffice-commits] online.git: Branch 'private/tml/cancellation' - 3 commits - loolwsd/LoadTest.cpp loolwsd/LOOLSession.cpp loolwsd/LOOLSession.hpp loolwsd/LOOLWSD.cpp loolwsd/loolwsd-systemplate-setup loolwsd/protocol.txt loolwsd/tsqueue.h

Tor Lillqvist tml at collabora.com
Tue Jun 9 05:58:06 PDT 2015


 loolwsd/LOOLSession.cpp           |   20 ++++--
 loolwsd/LOOLSession.hpp           |    9 ++-
 loolwsd/LOOLWSD.cpp               |  109 +++++++++++++++++++++++++++++---------
 loolwsd/LoadTest.cpp              |    3 -
 loolwsd/loolwsd-systemplate-setup |    2 
 loolwsd/protocol.txt              |    8 ++
 loolwsd/tsqueue.h                 |   65 ++++++++++++++++++++++
 7 files changed, 180 insertions(+), 36 deletions(-)

New commits:
commit 9e98a3898b0825c9d57b25df9905700a904c96c3
Author: Tor Lillqvist <tml at collabora.com>
Date:   Fri Jun 5 16:12:06 2015 +0300

    Add a "canceltiles" message to the protocol and handle it
    
    Implementing this Was harder than I first expected. The basic idea is as
    follows: The master process puts each message arriving from a client that
    isn't "canceltiles" into a (client-specific) queue. A separate thread that
    pulls messages from the queue at its own pace and handles them as
    before. Incoming "canceltiles" messages are handled specially, though: The
    queue is emptied of "tile" messages.
    
    The above sounds simple but there are several details that were a bit tricky
    to get right.

diff --git a/loolwsd/LOOLSession.cpp b/loolwsd/LOOLSession.cpp
index 5b30949..159955b 100644
--- a/loolwsd/LOOLSession.cpp
+++ b/loolwsd/LOOLSession.cpp
@@ -87,11 +87,21 @@ LOOLSession::~LOOLSession()
 
 void LOOLSession::sendTextFrame(const std::string& text)
 {
+    std::unique_lock<std::mutex> lock(_mutex);
+
     _ws->sendFrame(text.data(), text.size());
 }
 
 void LOOLSession::sendBinaryFrame(const char *buffer, int length)
 {
+    std::unique_lock<std::mutex> lock(_mutex);
+
+    if (length > 1000)
+    {
+        std::string nextmessage = "nextmessage: size=" + std::to_string(length);
+        _ws->sendFrame(nextmessage.data(), nextmessage.size());
+    }
+
     _ws->sendFrame(buffer, length, WebSocket::FRAME_BINARY);
 }
 
@@ -529,8 +539,6 @@ void MasterProcessSession::sendTile(const char *buffer, int length, StringTokeni
         cachedTile->read(output.data() + pos, size);
         cachedTile->close();
 
-        sendTextFrame("nextmessage: size=" + std::to_string(output.size()));
-
         sendBinaryFrame(output.data(), output.size());
 
         return;
@@ -628,7 +636,7 @@ void MasterProcessSession::forwardToPeer(const char *buffer, int length)
     auto peer = _peer.lock();
     if (!peer)
         return;
-    peer->_ws->sendFrame(buffer, length, WebSocket::FRAME_BINARY);
+    peer->sendBinaryFrame(buffer, length);
 }
 
 ChildProcessSession::ChildProcessSession(std::shared_ptr<WebSocket> ws, LibreOfficeKit *loKit) :
@@ -893,8 +901,6 @@ void ChildProcessSession::sendTile(const char *buffer, int length, StringTokeniz
 
     delete[] pixmap;
 
-    sendTextFrame("nextmessage: size=" + std::to_string(output.size()));
-
     sendBinaryFrame(output.data(), output.size());
 }
 
diff --git a/loolwsd/LOOLSession.hpp b/loolwsd/LOOLSession.hpp
index 93fee3c..2fd7d0b 100644
--- a/loolwsd/LOOLSession.hpp
+++ b/loolwsd/LOOLSession.hpp
@@ -69,6 +69,9 @@ protected:
 
     // In the master, the actual URL. In the child, the copy inside the chroot jail.
     std::string _docURL;
+
+private:
+    std::mutex _mutex;
 };
 
 template<typename charT, typename traits>
diff --git a/loolwsd/LOOLWSD.cpp b/loolwsd/LOOLWSD.cpp
index 18c21b3..cdced5f 100644
--- a/loolwsd/LOOLWSD.cpp
+++ b/loolwsd/LOOLWSD.cpp
@@ -86,6 +86,7 @@ DEALINGS IN THE SOFTWARE.
 #include "LOOLProtocol.hpp"
 #include "LOOLSession.hpp"
 #include "LOOLWSD.hpp"
+#include "tsqueue.h"
 #include "Util.hpp"
 
 using namespace LOOLProtocol;
@@ -120,6 +121,36 @@ using Poco::Util::Option;
 using Poco::Util::OptionSet;
 using Poco::Util::ServerApplication;
 
+class FromClientQueueHandler: public Runnable
+{
+public:
+    FromClientQueueHandler(tsqueue<std::string>& queue):
+        _queue(queue)
+    {
+    }
+
+    void setSession(std::shared_ptr<MasterProcessSession> session)
+    {
+        _session = session;
+    }
+
+    void run() override
+    {
+        while (true)
+        {
+            std::string input = _queue.get();
+            if (input == "eof")
+                break;
+            if (!_session->handleInput(input.c_str(), input.size()))
+                break;
+        }
+    }
+
+private:
+    std::shared_ptr<MasterProcessSession> _session;
+    tsqueue<std::string>& _queue;
+};
+
 class WebSocketRequestHandler: public HTTPRequestHandler
     /// Handle a WebSocket connection.
 {
@@ -139,26 +170,37 @@ public:
         }
 
         Application& app = Application::instance();
+
+        tsqueue<std::string> queue;
+        Thread queueHandlerThread;
+        FromClientQueueHandler handler(queue);
+
         try
         {
             try
             {
                 std::shared_ptr<WebSocket> ws(new WebSocket(request, response));
 
-                std::shared_ptr<MasterProcessSession> session;
+                LOOLSession::Kind kind;
 
                 if (request.getURI() == LOOLWSD::CHILD_URI && request.serverAddress().port() == LOOLWSD::MASTER_PORT_NUMBER)
-                {
-                    session.reset(new MasterProcessSession(ws, LOOLSession::Kind::ToPrisoner));
-                }
+                    kind = LOOLSession::Kind::ToPrisoner;
                 else
+                    kind = LOOLSession::Kind::ToClient;
+
+                std::shared_ptr<MasterProcessSession> session(new MasterProcessSession(ws, kind));
+
+                // For ToClient sessions, we store incoming messages in a queue and have a separate
+                // thread that handles them. This is so that we can empty the queue when we get a
+                // "canceltiles" message.
+                if (kind == LOOLSession::Kind::ToClient)
                 {
-                    session.reset(new MasterProcessSession(ws, LOOLSession::Kind::ToClient));
+                    handler.setSession(session);
+                    queueHandlerThread.start(handler);
                 }
 
-                // Loop, receiving WebSocket messages either from the
-                // client, or from the child process (to be forwarded to
-                // the client).
+                // Loop, receiving WebSocket messages either from the client, or from the child
+                // process (to be forwarded to the client).
                 int flags;
                 int n;
                 ws->setReceiveTimeout(0);
@@ -167,25 +209,43 @@ public:
                     char buffer[100000];
                     n = ws->receiveFrame(buffer, sizeof(buffer), flags);
 
+                    std::string firstLine = getFirstLine(buffer, n);
+                    StringTokenizer tokens(firstLine, " ", StringTokenizer::TOK_IGNORE_EMPTY | StringTokenizer::TOK_TRIM);
+
                     if (n > 0 && (flags & WebSocket::FRAME_OP_BITMASK) != WebSocket::FRAME_OP_CLOSE)
                     {
-                        if (!session->handleInput(buffer, n))
-                            n = 0;
-                    }
-                    if (n > 0 && (flags & WebSocket::FRAME_OP_BITMASK) != WebSocket::FRAME_OP_CLOSE)
-                    {
-                        std::string firstLine = getFirstLine(buffer, n);
-                        StringTokenizer tokens(firstLine, " ", StringTokenizer::TOK_IGNORE_EMPTY | StringTokenizer::TOK_TRIM);
-
-                        int size;
-                        if (tokens.count() == 2 && tokens[0] == "nextmessage:" && getTokenInteger(tokens[1], "size", size) && size > 0)
+                        if (kind == LOOLSession::Kind::ToClient && firstLine.size() == static_cast<std::string::size_type>(n))
                         {
-                            char largeBuffer[size];
-
-                            n = ws->receiveFrame(largeBuffer, size, flags);
-                            if (n > 0 && (flags & WebSocket::FRAME_OP_BITMASK) != WebSocket::FRAME_OP_CLOSE)
+                            // Check if it is a "canceltiles" and in that case remove outstanding
+                            // "tile" messages from the queue.
+                            if (tokens.count() == 1 && tokens[0] == "canceltiles")
+                            {
+                                queue.remove_if([](std::string& x){ return x.find("tile ") == 0;});
+                            }
+                            else
+                            {
+                                queue.put(firstLine);
+                            }
+                        }
+                        else
+                        {
+                            // Check if it is a "nextmessage:" and in that case read the large
+                            // follow-up message separately, and handle that only.
+                            int size;
+                            if (tokens.count() == 2 && tokens[0] == "nextmessage:" && getTokenInteger(tokens[1], "size", size) && size > 0)
+                            {
+                                char largeBuffer[size];
+
+                                n = ws->receiveFrame(largeBuffer, size, flags);
+                                if (n > 0 && (flags & WebSocket::FRAME_OP_BITMASK) != WebSocket::FRAME_OP_CLOSE)
+                                {
+                                    if (!session->handleInput(largeBuffer, n))
+                                        n = 0;
+                                }
+                            }
+                            else
                             {
-                                if (!session->handleInput(largeBuffer, n))
+                                if (!session->handleInput(buffer, n))
                                     n = 0;
                             }
                         }
@@ -215,6 +275,9 @@ public:
         {
             app.logger().error(Util::logPrefix() + "IOException: " + exc.message());
         }
+        queue.clear();
+        queue.put("eof");
+        queueHandlerThread.join();
     }
 };
 
diff --git a/loolwsd/LoadTest.cpp b/loolwsd/LoadTest.cpp
index 7b7ca38..c0c2eed 100644
--- a/loolwsd/LoadTest.cpp
+++ b/loolwsd/LoadTest.cpp
@@ -241,8 +241,9 @@ private:
                     break;
             }
             y = ((y + 1) % ((output._height-1)/DOCTILESIZE + 1));
-            Thread::sleep(200);
+            Thread::sleep(50);
         }
+        sendTextFrame(ws, "canceltiles");
 
         Thread::sleep(10000);
 
diff --git a/loolwsd/protocol.txt b/loolwsd/protocol.txt
index 82d3b90..655dcba 100644
--- a/loolwsd/protocol.txt
+++ b/loolwsd/protocol.txt
@@ -11,6 +11,12 @@ tiles proactively (guessing what the client might need). Etc.
 client -> server
 ================
 
+canceltiles
+
+    All outstanding tile messages from the client to the server are
+    dropped and will not be handled. There is no guarantee of exacely
+    which tile: messages might still be sent back to the client.
+
 invalidatetiles part=<partNumber> tileposx=<xpos> tileposy=<ypos> tilewidth=<tileWidth> tileheight=<tileHeight>
 
     All parameters are numbers. Makes the server remove any cached
@@ -88,7 +94,7 @@ nextmessage: size=<byteSize>
     message). Can be ignored by clients using an API that can read
     arbitrarily large buffers from a WebSocket (like JavaScript), but
     must be handled by clients that cannot (like those using Poco
-    1.6.0).
+    1.6.0, like the "loadtest" program in the loolwsd sources).
 
 status: type=<typeName> parts=<numberOfParts> current=<currentPartNumber> width=<width> height=<height>
 
diff --git a/loolwsd/tsqueue.h b/loolwsd/tsqueue.h
new file mode 100644
index 0000000..9511efb
--- /dev/null
+++ b/loolwsd/tsqueue.h
@@ -0,0 +1,65 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * 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 INCLUDED_TSQUEUE_H
+#define INCLUDED_TSQUEUE_H
+
+#include "config.h"
+
+#include <condition_variable>
+#include <mutex>
+#include <deque>
+
+// Thread-safe queue
+
+template <class T>
+class tsqueue
+{
+public:
+    void put(const T& value)
+    {
+        std::unique_lock<std::mutex> lock(_mutex);
+        _queue.push_back(value);
+        lock.unlock();
+        _cv.notify_one();
+    }
+
+    T get()
+    {
+        std::unique_lock<std::mutex> lock(_mutex);
+        _cv.wait(lock, [this] { return _queue.size() > 0; });
+        T result = _queue.front();
+        _queue.pop_front();
+        return result;
+    }
+
+    void clear()
+    {
+        std::unique_lock<std::mutex> lock(_mutex);
+        while (_queue.size())
+            _queue.pop_front();
+    }
+
+    template<class UnaryPredicate>
+    void remove_if(UnaryPredicate p)
+    {
+        std::unique_lock<std::mutex> lock(_mutex);
+        _queue.erase(std::remove_if(_queue.begin(), _queue.end(), p),
+                     _queue.end());
+    }
+
+private:
+    std::mutex _mutex;
+    std::condition_variable _cv;
+    std::deque<T> _queue;
+};
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
commit f849c5f31e43517804294b129e0c56bb65906f3c
Author: Tor Lillqvist <tml at collabora.com>
Date:   Mon Jun 8 16:58:34 2015 +0300

    Clarify usage message

diff --git a/loolwsd/loolwsd-systemplate-setup b/loolwsd/loolwsd-systemplate-setup
index 8af0517..7e310fb 100755
--- a/loolwsd/loolwsd-systemplate-setup
+++ b/loolwsd/loolwsd-systemplate-setup
@@ -1,6 +1,6 @@
 #!/bin/bash
 
-test $# -eq 2 || { echo "Usage: $0 <chroot template directory> <LO installation directory>"; exit 1; }
+test $# -eq 2 || { echo "Usage: $0 <chroot template directory for system libs to create> <LO installation directory>"; exit 1; }
 
 # No provision for spaces or other weird characters in pathnames. So sue me.
 
commit b5856cb61cd2d1aa185cabf8054da5ef03d4a55c
Author: Tor Lillqvist <tml at collabora.com>
Date:   Mon Jun 8 16:35:52 2015 +0300

    The buffer parameter to handleInput() can be const

diff --git a/loolwsd/LOOLSession.cpp b/loolwsd/LOOLSession.cpp
index 9843832..5b30949 100644
--- a/loolwsd/LOOLSession.cpp
+++ b/loolwsd/LOOLSession.cpp
@@ -123,7 +123,7 @@ MasterProcessSession::~MasterProcessSession()
     }
 }
 
-bool MasterProcessSession::handleInput(char *buffer, int length)
+bool MasterProcessSession::handleInput(const char *buffer, int length)
 {
     Application::instance().logger().information(Util::logPrefix() + "Input: " + getAbbreviatedMessage(buffer, length));
 
@@ -647,7 +647,7 @@ ChildProcessSession::~ChildProcessSession()
     Util::shutdownWebSocket(*_ws);
 }
 
-bool ChildProcessSession::handleInput(char *buffer, int length)
+bool ChildProcessSession::handleInput(const char *buffer, int length)
 {
     Application& app = Application::instance();
 
diff --git a/loolwsd/LOOLSession.hpp b/loolwsd/LOOLSession.hpp
index c73456c..93fee3c 100644
--- a/loolwsd/LOOLSession.hpp
+++ b/loolwsd/LOOLSession.hpp
@@ -53,7 +53,7 @@ protected:
 
     const Kind _kind;
 
-    virtual bool handleInput(char *buffer, int length) = 0;
+    virtual bool handleInput(const char *buffer, int length) = 0;
 
     void sendBinaryFrame(const char *buffer, int length);
 
@@ -94,7 +94,7 @@ public:
     MasterProcessSession(std::shared_ptr<Poco::Net::WebSocket> ws, Kind kind);
     virtual ~MasterProcessSession();
 
-    virtual bool handleInput(char *buffer, int length) override;
+    virtual bool handleInput(const char *buffer, int length) override;
 
     bool haveSeparateProcess();
 
@@ -152,7 +152,7 @@ public:
     ChildProcessSession(std::shared_ptr<Poco::Net::WebSocket> ws, LibreOfficeKit *loKit);
     virtual ~ChildProcessSession();
 
-    virtual bool handleInput(char *buffer, int length) override;
+    virtual bool handleInput(const char *buffer, int length) override;
 
     virtual bool getStatus(const char *buffer, int length);
 


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