refactor(linux/xdgportal): Unify display_name generation/matching in pipewire_streaminfo_t

Reduce complexity in other code parts and have the display_name generation/matching done next to each other for better maintainability.

Author: Kishi85

src/platform/linux/portalgrab.cpp

@@ -180,6 +180,45 @@ namespace portal {
     int pos_x;
     int pos_y;
     std::string monitor_name;
+
+    std::string to_display_name() {
+      if (monitor_name.length() > 0) {
+        return std::format("n{}", monitor_name);
+      }
+      return std::format("p{},{},{},{}", pos_x, pos_y, width, height);
+    }
+    bool match_display_name(const std::string &display_name) const{
+      // Empty display_name never matches
+      if (display_name.empty()) {
+        return false;
+      }
+      // Method 1: Display_name starts with 'n' match by monitor_name starting from pos 1
+      if (display_name[0] == 'n') {
+        return display_name.substr(1) == monitor_name;
+      }
+      // Method 2: Display_name starts with 'p' match by position+resolution starting from pos 1
+      if (display_name[0] == 'p') {
+        auto stringstream = std::stringstream(display_name.substr(1));
+        std::string stringvalue;
+        std::vector<int> values;
+        constexpr char display_name_delimiter = ',';
+        while (std::getline(stringstream, stringvalue, display_name_delimiter)) {
+          if (std::ranges::all_of(stringvalue, ::isdigit)) {
+            values.emplace_back(std::stoi(stringvalue));
+          } else {
+            BOOST_LOG(debug) << "[portalgrab] Failed to parse int value: '"sv << stringvalue << "'";
+          }
+        }
+        // Check if the vector has 4 values (pos_x, pos_y, width, height) from display_names formatting
+        if (values.size() != 4) {
+          BOOST_LOG(debug) << "[portalgrab] Display name does not match expected format 'x,y,w,h': '"sv << display_name << "'";
+          return false;
+        }
+        return pos_x == values[0] && pos_y == values[1] && width == values[2] && height == values[3];
+      }
+      // All matching methods have failed. No match!
+      return false;
+    }
   };
 
   class dbus_t {
@@ -1316,9 +1355,17 @@ namespace portal {
         return -1;
       }
       // Match display_name to a stream from the pipewire_streams vector
-      pipewire_streaminfo_t stream = match_display_name_to_stream(pipewire_streams, display_name);
+      bool use_fallback = true;
+      pipewire_streaminfo_t stream;
+      for (const auto &stream_ : pipewire_streams) {
+        if (stream_.match_display_name(display_name)) {
+          stream = stream_;
+          use_fallback = false;
+          break;
+        }
+      }
       // Fall back to first stream if we cannot match the given display_name to a stream in currently available streams.
-      if (stream.width < 0 || stream.height < 0) {
+      if (use_fallback) {
         BOOST_LOG(info) << "[portalgrab] Using first available stream as no matching stream was found for: '"sv << display_name << "'";
         stream = pipewire_streams[0];
       }
@@ -1681,50 +1728,6 @@ namespace portal {
       return 0;
     }
 
-    static pipewire_streaminfo_t match_display_name_to_stream(const std::vector<pipewire_streaminfo_t> &pipewire_streams, const std::string &display_name) {
-      const auto invalid_stream = pipewire_streaminfo_t {-1, -1, -1, -1, -1};
-      // Empty display_names cannot be mapped to a valid stream
-      if (display_name.empty()) {
-        return invalid_stream;
-      }
-      // Display_name starts with 'n' match by monitor_name starting from pos 1
-      if (!display_name.empty() && display_name[0] == 'n') {
-        auto monitor_name = display_name.substr(1);
-        for (const auto &stream : pipewire_streams) {
-          if (stream.monitor_name == monitor_name) {
-            return stream;
-          }
-        }
-      }
-      // Display_name starts with 'p' match by position+resolution starting from pos 1
-      if (!display_name.empty() && display_name[0] == 'p') {
-        auto stringstream = std::stringstream(display_name.substr(1));
-        std::string stringvalue;
-        std::vector<int> values;
-        constexpr char display_name_delimiter = ',';
-        while (std::getline(stringstream, stringvalue, display_name_delimiter)) {
-          if (std::ranges::all_of(stringvalue, ::isdigit)) {
-            values.emplace_back(std::stoi(stringvalue));
-          } else {
-            BOOST_LOG(warning) << "[portalgrab] Failed to parse int value: '"sv << stringvalue << "'";
-          }
-        }
-        // Check if the vector has 4 values (pos_x, pos_y, width, height) from display_names formatting
-        if (values.size() != 4) {
-          BOOST_LOG(warning) << "[portalgrab] Display name does not match expected format 'x,y,w,h': '"sv << display_name << "'";
-          return invalid_stream;
-        }
-        // Determine correct pipewire_node by iterating pipewire_streams and matching position and resolution
-        for (const auto &stream : pipewire_streams) {
-          if (stream.pos_x == values[0] && stream.pos_y == values[1] && stream.width == values[2] && stream.height == values[3]) {
-            return stream;
-          }
-        }
-      }
-      // If we reach this point, no matching stream was found.
-      return invalid_stream;
-    }
-
     platf::mem_type_e mem_type;
     wl::display_t wl_display;
     pipewire_t pipewire;
@@ -1758,21 +1761,6 @@ namespace platf {
     return portal;
   }
 
-  std::vector<std::string> portal_streams_to_display_names(const std::vector<portal::pipewire_streaminfo_t> &pipewire_streams, const bool log) {
-    std::vector<std::string> display_names;
-    for (auto stream : pipewire_streams) {
-      if (log) {
-        BOOST_LOG(info) << "[portalgrab] Found stream for display: '"sv << stream.monitor_name << "' position: "sv << stream.pos_x << "x"sv << stream.pos_y << " resolution: "sv << stream.width << "x"sv << stream.height;
-      }
-      if (stream.monitor_name.length() > 0) {
-        display_names.emplace_back(std::format("n{}", stream.monitor_name));
-      } else {
-        display_names.emplace_back(std::format("p{},{},{},{}", stream.pos_x, stream.pos_y, stream.width, stream.height));
-      }
-    }
-    return display_names;
-  }
-
   std::vector<std::string> portal_display_names() {
     auto dbus = std::make_shared<portal::dbus_t>();
 
@@ -1787,14 +1775,21 @@ namespace platf {
       BOOST_LOG(warning) << "[portalgrab] Failed to connect to portal. Cannot enumerate displays, returning empty list.";
       return {};
     }
-    std::vector<std::string> dbus_display_names = portal_streams_to_display_names(dbus->pipewire_streams, true);
+    std::vector<std::string> dbus_display_names;
+    for (auto stream_ : dbus->pipewire_streams) {
+      BOOST_LOG(info) << "[portalgrab] Found stream for display: '"sv << stream_.monitor_name << "' position: "sv << stream_.pos_x << "x"sv << stream_.pos_y << " resolution: "sv << stream_.width << "x"sv << stream_.height;
+      dbus_display_names.emplace_back(stream_.to_display_name());
+    }
     // Release the new portal as soon as possible to properly release related resources early.
     dbus.reset();
     // Get all display_names from cache
     int cache_pipewire_fd;
     std::vector<portal::pipewire_streaminfo_t> cache_pipewire_streams;
     portal::session_cache_t::instance().get_or_create_session(cache_pipewire_fd, cache_pipewire_streams);
-    std::vector<std::string> cache_display_names = portal_streams_to_display_names(cache_pipewire_streams, false);
+    std::vector<std::string> cache_display_names;
+    for (auto stream_ : cache_pipewire_streams) {
+      cache_display_names.emplace_back(stream_.to_display_name());
+    }
     // Close the unused duplicated pipewire_fd from get_or_create_session
     close(cache_pipewire_fd);
     // Compare dbus with cache display names and invalidate the cache if things differ