1 files changed, 333 insertions, 0 deletions
diff --git a/indra/media_plugins/cef/linux/volume_catcher_pipewire.cpp b/indra/media_plugins/cef/linux/volume_catcher_pipewire.cpp
new file mode 100755
index 0000000000..a8f1366d6f
--- /dev/null
+++ b/indra/media_plugins/cef/linux/volume_catcher_pipewire.cpp
@@ -0,0 +1,333 @@
+/**
+ * @file volume_catcher_pipewire.cpp
+ * @brief A Linux-specific, PipeWire-specific hack to detect and volume-adjust new audio sources
+ *
+ * @cond
+ * $LicenseInfo:firstyear=2010&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2010, Linden Research, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ * @endcond
+ */
+
+/*
+  The high-level design is as follows:
+  1) Connect to the PipeWire daemon
+  2) Find all existing and new audio nodes
+  3) Examine PID and parent PID's to see if it belongs to our process
+  4) If so, tell PipeWire to adjust the volume of that node
+  5) Keep a list of all audio nodes and adjust when we setVolume()
+ */
+
+#include "linden_common.h"
+
+#include "volume_catcher_linux.h"
+
+extern "C" {
+#include <spa/pod/builder.h>
+#include <spa/param/props.h>
+}
+
+SymbolGrabber pwSymbolGrabber;
+
+#include "volume_catcher_pipewire_syms.inc"
+
+////////////////////////////////////////////////////
+
+VolumeCatcherPipeWire::VolumeCatcherPipeWire()
+{
+    init();
+}
+
+VolumeCatcherPipeWire::~VolumeCatcherPipeWire()
+{
+    cleanup();
+}
+
+static void registryEventGlobal(
+    void *data, uint32_t id, uint32_t permissions, const char *type,
+    uint32_t version, const struct spa_dict *props)
+{
+    static_cast<VolumeCatcherPipeWire*>(data)->handleRegistryEventGlobal(
+        id, permissions, type, version, props
+    );
+}
+
+static const struct pw_registry_events REGISTRY_EVENTS = {
+    .version = PW_VERSION_REGISTRY_EVENTS,
+    .global = registryEventGlobal,
+};
+
+bool VolumeCatcherPipeWire::loadsyms(std::string pw_dso_name)
+{
+    return pwSymbolGrabber.grabSymbols({ pw_dso_name });
+}
+
+void VolumeCatcherPipeWire::init()
+{
+    LL_DEBUGS() << "init" << LL_ENDL;
+
+    mGotSyms = loadsyms("libpipewire-0.3.so.0");
+
+    if (!mGotSyms)
+        return;
+
+    LL_DEBUGS() << "successfully got symbols" << LL_ENDL;
+
+    llpw_init(nullptr, nullptr);
+
+    mThreadLoop = llpw_thread_loop_new("SL Plugin Volume Adjuster", nullptr);
+
+    if (!mThreadLoop)
+        return;
+
+    // i dont think we need to lock this early
+    // std::lock_guard pwLock(*this);
+
+    mContext = llpw_context_new(
+        llpw_thread_loop_get_loop(mThreadLoop), nullptr, 0
+    );
+
+    if (!mContext)
+        return;
+
+    mCore = llpw_context_connect(mContext, nullptr, 0);
+
+    if (!mCore)
+        return;
+
+    mRegistry = pw_core_get_registry(mCore, PW_VERSION_REGISTRY, 0);
+
+    LL_DEBUGS() << "pw_core_get_registry: " <<  (mRegistry?"success":"nullptr") << LL_ENDL;
+
+    spa_zero(mRegistryListener);
+
+    pw_registry_add_listener(
+        mRegistry, &mRegistryListener, &REGISTRY_EVENTS, this
+    );
+
+    llpw_thread_loop_start(mThreadLoop);
+
+    LL_DEBUGS() << "thread loop started" << LL_ENDL;
+}
+
+void VolumeCatcherPipeWire::cleanup()
+{
+    {
+        std::unique_lock childNodesLock(mChildNodesMutex);
+        for (auto *childNode: mChildNodes)
+            childNode->destroy();
+
+        mChildNodes.clear();
+    }
+
+    {
+        std::unique_lock pwLock(mCleanupMutex);
+        if (mRegistry)
+            llpw_proxy_destroy((struct pw_proxy *) mRegistry);
+
+        spa_zero(mRegistryListener);
+
+        if (mCore)
+            llpw_core_disconnect(mCore);
+        if (mContext)
+            llpw_context_destroy(mContext);
+    }
+
+    if (!mThreadLoop)
+        return;
+
+    llpw_thread_loop_stop(mThreadLoop);
+    llpw_thread_loop_destroy(mThreadLoop);
+
+    LL_DEBUGS() << "cleanup done" << LL_ENDL;
+}
+
+void VolumeCatcherPipeWire::lock()
+{
+    if (!mThreadLoop)
+        return;
+
+    llpw_thread_loop_lock(mThreadLoop);
+}
+
+void VolumeCatcherPipeWire::unlock()
+{
+    if (!mThreadLoop)
+        return;
+
+    llpw_thread_loop_unlock(mThreadLoop);
+}
+
+const uint32_t channels = 1;
+const float resetVolumes[channels] = { 1.0f };
+
+void VolumeCatcherPipeWire::ChildNode::updateVolume()
+{
+    if (!mActive)
+        return;
+
+    F32 volume = std::clamp(mImpl->mVolume, 0.0f, 1.0f);
+
+    const float volumes[channels] = { volume };
+
+    uint8_t buffer[512];
+
+    spa_pod_builder builder;
+    spa_pod_builder_init(&builder, buffer, sizeof(buffer));
+
+    spa_pod_frame frame;
+    spa_pod_builder_push_object(&builder, &frame, SPA_TYPE_OBJECT_Props, SPA_PARAM_Props);
+
+    // resets system-wide memorized volume for chromium (not google chrome) to 100%
+    spa_pod_builder_prop(&builder, SPA_PROP_channelVolumes, 0);
+    spa_pod_builder_array(&builder, sizeof(float), SPA_TYPE_Float, channels, resetVolumes);
+
+    // sets temporary volume
+    spa_pod_builder_prop(&builder, SPA_PROP_softVolumes, 0);
+    spa_pod_builder_array(&builder, sizeof(float), SPA_TYPE_Float, channels, volumes);
+
+    spa_pod* pod = static_cast<spa_pod*>(spa_pod_builder_pop(&builder, &frame));
+
+    {
+        std::lock_guard pwLock(*mImpl);
+        pw_node_set_param(mProxy, SPA_PARAM_Props, 0, pod);
+    }
+}
+
+void VolumeCatcherPipeWire::ChildNode::destroy()
+{
+    if (!mActive)
+        return;
+
+    mActive = false;
+
+    {
+        std::unique_lock childNodesLock(mImpl->mChildNodesMutex);
+        mImpl->mChildNodes.erase(this);
+    }
+
+    spa_hook_remove(&mNodeListener);
+    spa_hook_remove(&mProxyListener);
+
+    {
+        std::lock_guard pwLock(*mImpl);
+        llpw_proxy_destroy(mProxy);
+    }
+}
+
+static void nodeEventInfo(void* data, const struct pw_node_info* info)
+{
+    const char* processId = spa_dict_lookup(info->props, PW_KEY_APP_PROCESS_ID);
+
+    if (processId == nullptr)
+        return;
+
+    pid_t pid = atoll(processId);
+
+    if (!isPluginPid(pid))
+        return;
+
+    const char* appName = spa_dict_lookup(info->props, PW_KEY_APP_NAME);
+    LL_DEBUGS() << "got app: " << appName << LL_ENDL;
+
+    auto* const childNode = static_cast<VolumeCatcherPipeWire::ChildNode*>(data);
+    LL_DEBUGS() << "init volume: " << childNode->mImpl->mVolume  << LL_ENDL;
+
+    childNode->updateVolume();
+
+    {
+        std::lock_guard childNodesLock(childNode->mImpl->mChildNodesMutex);
+        childNode->mImpl->mChildNodes.insert(childNode);
+    }
+}
+
+static const struct pw_node_events NODE_EVENTS = {
+    .version = PW_VERSION_CLIENT_EVENTS,
+    .info = nodeEventInfo,
+};
+
+static void proxyEventDestroy(void* data)
+{
+    auto* const childNode = static_cast<VolumeCatcherPipeWire::ChildNode*>(data);
+    childNode->destroy();
+}
+
+static void proxyEventRemoved(void* data)
+{
+    auto* const childNode = static_cast<VolumeCatcherPipeWire::ChildNode*>(data);
+    childNode->destroy();
+}
+
+static const struct pw_proxy_events PROXY_EVENTS = {
+    .version = PW_VERSION_PROXY_EVENTS,
+    .destroy = proxyEventDestroy,
+    .removed = proxyEventRemoved,
+};
+
+void VolumeCatcherPipeWire::handleRegistryEventGlobal(
+    uint32_t id, uint32_t permissions, const char *type, uint32_t version,
+    const struct spa_dict *props)
+{
+    if (props == nullptr  || type == nullptr || strcmp(type, PW_TYPE_INTERFACE_Node) != 0)
+        return;
+
+    const char* mediaClass = spa_dict_lookup(props, PW_KEY_MEDIA_CLASS);
+
+    if (mediaClass == nullptr || strcmp(mediaClass, "Stream/Output/Audio") != 0)
+        return;
+
+    pw_proxy* proxy = static_cast<pw_proxy*>(
+        pw_registry_bind(mRegistry, id, type, PW_VERSION_CLIENT, sizeof(ChildNode))
+    );
+
+    auto* const childNode = static_cast<ChildNode*>(llpw_proxy_get_user_data(proxy));
+
+    childNode->mActive = true;
+    childNode->mProxy = proxy;
+    childNode->mImpl = this;
+
+    pw_node_add_listener(proxy, &childNode->mNodeListener, &NODE_EVENTS, childNode);
+    llpw_proxy_add_listener(proxy, &childNode->mProxyListener, &PROXY_EVENTS, childNode);
+}
+
+void VolumeCatcherPipeWire::setVolume(F32 volume)
+{
+    LL_DEBUGS() << "setting volume to: " << volume << LL_ENDL;
+
+    mVolume = volume;
+
+    {
+        std::unique_lock childNodeslock(mChildNodesMutex);
+        std::unordered_set<ChildNode *> copyOfChildNodes(mChildNodes);
+
+        LL_DEBUGS() << "found " << copyOfChildNodes.size() << " child nodes" << LL_ENDL;
+
+        for (auto* childNode : copyOfChildNodes)
+            childNode->updateVolume();
+    }
+}
+
+void VolumeCatcherPipeWire::setPan(F32 pan)
+{
+}
+
+void VolumeCatcherPipeWire::pump()
+{
+}