[Spice-devel] [RFC spice-streaming-agent 4/4] concrete-agent: prioritize requested codec for plugin selection

[Kevin Pouget]

This patch gives more priority to the requested video codecs when
selecting the FrameCapture plugin, instead of its hard-coded rank.

The client_codecs storage structure is changed from 'set' to 'vector',
as the codec order is not preserved by the set structure..

Signed-off-by: Kevin Pouget <kpouget at redhat.com>
---
 src/concrete-agent.cpp        | 38 +++++++++++++++++------------------
 src/concrete-agent.hpp        |  2 +-
 src/spice-streaming-agent.cpp |  2 +-
 src/stream-port.cpp           |  2 +-
 src/stream-port.hpp           |  4 ++--
 5 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/src/concrete-agent.cpp b/src/concrete-agent.cpp
index 336bd09..683fa26 100644
--- a/src/concrete-agent.cpp
+++ b/src/concrete-agent.cpp
@@ -111,7 +111,7 @@ void ConcreteAgent::LoadPlugin(const std::string &plugin_filename)
     }
 }
 
-FrameCapture *ConcreteAgent::GetBestFrameCapture(const std::set<SpiceVideoCodecType>& codecs)
+FrameCapture *ConcreteAgent::GetBestFrameCapture(const std::vector<SpiceVideoCodecType>& codecs)
 {
     std::vector<std::pair<unsigned, std::shared_ptr<Plugin>>> sorted_plugins;
 
@@ -121,24 +121,24 @@ FrameCapture *ConcreteAgent::GetBestFrameCapture(const std::set<SpiceVideoCodecT
     }
     sort(sorted_plugins.rbegin(), sorted_plugins.rend());
 
-    // return first not null
-    for (const auto& plugin: sorted_plugins) {
-        if (plugin.first == DontUse) {
-            break;
-        }
-        // check client supports the codec
-        if (codecs.find(plugin.second->VideoCodecType()) == codecs.end())
-            continue;
-
-        FrameCapture *capture;
-        try {
-            capture = plugin.second->CreateCapture();
-        } catch (const std::exception &err) {
-            syslog(LOG_ERR, "Error creating capture engine: %s", err.what());
-            continue;
-        }
-        if (capture) {
-            return capture;
+    for (const auto& codec_type: codecs) {
+        // find the plugin with the highest rank for this codec type
+        for (const auto& plugin: sorted_plugins) {
+            if (plugin.first == DontUse) {
+                continue;
+            }
+
+            // check client supports the codec
+            if (plugin.second->VideoCodecType() != codec_type) {
+                continue;
+            }
+
+            try {
+                return plugin.second->CreateCapture();
+            } catch (const std::exception &err) {
+                syslog(LOG_ERR, "Error creating capture engine: %s", err.what());
+                continue;
+            }
         }
     }
     return nullptr;
diff --git a/src/concrete-agent.hpp b/src/concrete-agent.hpp
index 6d1be35..0399bab 100644
--- a/src/concrete-agent.hpp
+++ b/src/concrete-agent.hpp
@@ -33,7 +33,7 @@ public:
     void Register(const std::shared_ptr<Plugin>& plugin) override;
     const ConfigureOption* Options() const override;
     void LoadPlugins(const std::string &directory);
-    FrameCapture *GetBestFrameCapture(const std::set<SpiceVideoCodecType>& codecs);
+    FrameCapture *GetBestFrameCapture(const std::vector<SpiceVideoCodecType>& codecs);
     __attribute__ ((format (printf, 2, 3)))
     void LogStat(const char* format, ...) override;
 private:
diff --git a/src/spice-streaming-agent.cpp b/src/spice-streaming-agent.cpp
index d274b5f..15c2732 100644
--- a/src/spice-streaming-agent.cpp
+++ b/src/spice-streaming-agent.cpp
@@ -128,7 +128,7 @@ private:
 static bool capture_in_progress = false;
 static bool reset_requested = false;
 static bool quit_requested = false;
-static std::set<SpiceVideoCodecType> client_codecs;
+static std::vector<SpiceVideoCodecType> client_codecs;
 
 static bool have_something_to_read(StreamPort &stream_port, bool blocking)
 {
diff --git a/src/stream-port.cpp b/src/stream-port.cpp
index 2670120..0d08d50 100644
--- a/src/stream-port.cpp
+++ b/src/stream-port.cpp
@@ -43,7 +43,7 @@ StartStopMessage InboundMessage::get_payload<StartStopMessage>()
     }
 
     for (size_t i = 1; i <= data[0]; ++i) {
-        msg.client_codecs.insert((SpiceVideoCodecType) data[i]);
+        msg.client_codecs.push_back((SpiceVideoCodecType) data[i]);
     }
 
     return msg;
diff --git a/src/stream-port.hpp b/src/stream-port.hpp
index 08473f7..b2f7520 100644
--- a/src/stream-port.hpp
+++ b/src/stream-port.hpp
@@ -16,7 +16,7 @@
 #include <string>
 #include <memory>
 #include <mutex>
-#include <set>
+#include <vector>
 
 
 namespace spice {
@@ -45,7 +45,7 @@ public:
 struct StartStopMessage
 {
     bool start_streaming = false;
-    std::set<SpiceVideoCodecType> client_codecs;
+    std::vector<SpiceVideoCodecType> client_codecs;
 };
 
 struct InCapabilitiesMessage {};
-- 
2.21.0