Detect Steam Protons across libraries

3 files changed, 62 insertions, 15 deletions

diff --git a/src/src/steamdetection.cpp b/src/src/steamdetection.cpp
index 7710edd..512b1fa 100644
--- a/src/src/steamdetection.cpp
+++ b/src/src/steamdetection.cpp
@@ -2,10 +2,13 @@
 
 #include <QDir>
 #include <QDirIterator>
+#include <QFile>
 #include <QFileInfo>
 #include <QStandardPaths>
 #include <uibase/log.h>
 
+#include "vdfparser.h"
+
 // ============================================================================
 // SteamProtonInfo
 // ============================================================================
@@ -56,6 +59,40 @@ QString findSteamPath()
   return {};
 }
 
+QStringList findSteamLibraryPaths()
+{
+  QStringList libraries;
+
+  const QString steamPath = findSteamPath();
+  if (steamPath.isEmpty())
+    return libraries;
+
+  auto addLibrary = [&](const QString& path) {
+    const QString cleanPath = QDir::cleanPath(path);
+    if (cleanPath.isEmpty() || libraries.contains(cleanPath))
+      return;
+    if (QFileInfo::exists(QDir(cleanPath).filePath(QStringLiteral("steamapps"))))
+      libraries.append(cleanPath);
+  };
+
+  addLibrary(steamPath);
+
+  QFile libraryFolders(QDir(steamPath).filePath(
+      QStringLiteral("steamapps/libraryfolders.vdf")));
+  if (!libraryFolders.open(QIODevice::ReadOnly | QIODevice::Text)) {
+    MOBase::log::debug("Steam libraryfolders.vdf not found at '{}'",
+                       libraryFolders.fileName());
+    return libraries;
+  }
+
+  const QString content = QString::fromUtf8(libraryFolders.readAll());
+  for (const QString& path : parseLibraryFolders(content)) {
+    addLibrary(path);
+  }
+
+  return libraries;
+}
+
 // ============================================================================
 // Proton Detection
 // ============================================================================
@@ -143,27 +180,28 @@ QVector<SteamProtonInfo> findSteamProtons()
 {
   QVector<SteamProtonInfo> protons;
 
-  const QString steamPath = findSteamPath();
-  if (steamPath.isEmpty())
+  const QStringList steamLibraries = findSteamLibraryPaths();
+  if (steamLibraries.isEmpty())
     return protons;
 
-  // 1. Steam's built-in Protons (only entries starting with "Proton").
-  {
+  // 1. Steam's built-in Protons across every Steam library. Steam may install
+  // tools like "Proton 10.0" under a secondary library's steamapps/common.
+  for (const QString& library : steamLibraries) {
     QVector<SteamProtonInfo> builtin;
-    scanProtonDir(steamPath + "/steamapps/common", true, builtin);
-    // Keep only entries whose folder name starts with "Proton". Proton 11
-    // had ntsync/futex deadlocks during wineboot -u on modern kernels; the
-    // workaround now lives in prefixsetuprunner (waitforexitandrun + ntsync
-    // env nudge) so we no longer blacklist it here.
+    scanProtonDir(QDir(library).filePath(QStringLiteral("steamapps/common")), true,
+                  builtin);
     for (auto& p : builtin) {
-      if (!p.name.startsWith(QStringLiteral("Proton")))
-        continue;
-      protons.append(std::move(p));
+      if (p.name.startsWith(QStringLiteral("Proton"))) {
+        protons.append(std::move(p));
+      }
     }
   }
 
   // 2. Custom Protons in user's compatibilitytools.d.
-  scanProtonDir(steamPath + "/compatibilitytools.d", false, protons);
+  for (const QString& library : steamLibraries) {
+    scanProtonDir(QDir(library).filePath(QStringLiteral("compatibilitytools.d")),
+                  false, protons);
+  }
 
   // 3. System-level Protons.
   scanProtonDir(QStringLiteral("/usr/share/steam/compatibilitytools.d"), false, protons);
diff --git a/src/src/steamdetection.h b/src/src/steamdetection.h
index fd8dc3f..4e0368f 100644
--- a/src/src/steamdetection.h
+++ b/src/src/steamdetection.h
@@ -26,6 +26,9 @@ struct SteamProtonInfo {
 /// Find the Steam installation path (returns empty string if not found).
 __attribute__((visibility("default"))) QString findSteamPath();
 
+/// Find all Steam library root paths, including secondary libraries.
+__attribute__((visibility("default"))) QStringList findSteamLibraryPaths();
+
 /// Find all installed Proton versions (Proton 10+ only, sorted newest first).
 __attribute__((visibility("default"))) QVector<SteamProtonInfo> findSteamProtons();
 
diff --git a/src/src/vdfparser.cpp b/src/src/vdfparser.cpp
index 1df8fe6..126be63 100644
--- a/src/src/vdfparser.cpp
+++ b/src/src/vdfparser.cpp
@@ -138,8 +138,14 @@ QStringList parseLibraryFolders(const QString& content)
     return paths;
 
   for (const VdfValue& entry : folders->asObject()) {
-    const QString path = entry.getString(QStringLiteral("path"));
-    if (!path.isEmpty())
+    QString path;
+    if (entry.isString()) {
+      path = entry.asString();
+    } else {
+      path = entry.getString(QStringLiteral("path"));
+    }
+
+    if (!path.isEmpty() && !paths.contains(path))
       paths.append(path);
   }
   return paths;