VFS perf fixes, icon/stylesheet compat, download filename fix

VFS:
- Open backing fd at mo2_open time for read-only handles so mo2_read can
  splice without re-opening the file on every read call.
- Bump RLIMIT_NOFILE at mount time to fit the resulting fd pressure when
  the game keeps hundreds of BSAs open.
- Dedicated node_cache_mutex so resolveByInode / mo2_lookup stop racing
  unordered_map writes while multiple tree_mutex readers are active.
- max_read=1MB + matching conn->max_read and raised max_readahead/max_write
  so the kernel merges Wine's small sequential reads into bigger FUSE
  requests.
- Per-op wall-clock counters in mo2_init() logs so we can distinguish VFS
  latency from game-side work.

Proton launch:
- Write dxvk.conf to the prefix and set DXVK_CONFIG_FILE to force
  dxvk.enableGraphicsPipelineLibrary=False, avoiding long GPL compile
  stalls on first run.

UI / plugin compat:
- Clamp IconDelegate's per-icon width to [8, 16] so narrow content
  columns don't trigger QIcon::pixmap(0,0) returning null and logging
  "failed to load icon" every repaint.
- Pre-create lowercase symlinks in the stylesheet directory so QSS files
  authored on Windows resolve url(foo.svg) when on-disk files are Foo.svg.
- Flip content icons empty-chessboard.png and facegen.png to 8-bit RGBA
  so Qt's built-in PNG reader loads them uniformly.
- Add mobase.Version.canonicalString shim for legacy Python plugins that
  still call the old VersionInfo method on appVersion()'s return.
- BSPluginList: compare normalized plugin name lists instead of byte
  hashes so the post-run case-fix refresh stops spuriously firing the
  "load order changed" dialog.
- BSPluginList disabled by default.

Download manager:
- Parse CDN URL with QUrl + QUrlQuery and read the filename from the
  response-content-disposition query param (RFC 6266 quoted / unquoted /
  ext-value forms), not QFileInfo on the raw URL.
- When the API or URL gives us a CDN object key (no archive extension),
  prefer the actual Content-Disposition header from the live response in
  metaDataChanged and downloadFinished.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

1 files changed, 231 insertions, 0 deletions

diff --git a/libs/installer_bsplugins/src/TESData/DataItem.cpp b/libs/installer_bsplugins/src/TESData/DataItem.cpp
new file mode 100644
index 0000000..c083aae
--- /dev/null
+++ b/libs/installer_bsplugins/src/TESData/DataItem.cpp
@@ -0,0 +1,231 @@
+#include "DataItem.h"
+
+#include <algorithm>
+#include <iterator>
+
+using namespace Qt::Literals::StringLiterals;
+
+namespace TESData
+{
+
+QString DataItem::makeName(TESFile::Type signature, const QString& name)
+{
+  const QByteArray sig =
+      QByteArray(signature.data(), signature.size()).toPercentEncoding("@"_ba);
+
+  if (!name.isEmpty()) {
+    return QStringLiteral("%1 - %2").arg(QString::fromLatin1(sig), name);
+  } else {
+    return QString::fromLatin1(sig);
+  }
+}
+
+QVariant DataItem::data(int fileIndex) const
+{
+  if (fileIndex < m_Data.size()) {
+    return m_Data[fileIndex];
+  }
+
+  return QVariant();
+}
+
+QVariant DataItem::displayData(int fileIndex) const
+{
+  if (fileIndex < m_DisplayData.size()) {
+    const auto& displayData = m_DisplayData[fileIndex];
+    if (displayData.isValid()) {
+      return displayData;
+    }
+  }
+
+  return data(fileIndex);
+}
+
+bool DataItem::isLosingConflict(int fileIndex, int fileCount) const
+{
+  if (m_ConflictType == ConflictType::Ignore ||
+      m_ConflictType == ConflictType::Benign ||
+      m_ConflictType == ConflictType::BenignIfAdded) {
+    return false;
+  }
+
+  if (!m_Data.isEmpty()) {
+    if (fileIndex >= m_Data.length()) {
+      return false;
+    } else if (fileCount > m_Data.length() &&
+               m_ConflictType != ConflictType::NormalIgnoreEmpty) {
+      return true;
+    }
+
+    for (int i = fileIndex + 1; i < m_Data.length(); ++i) {
+      if (hasConflict(m_Data[i], m_Data[fileIndex])) {
+        return true;
+      }
+    }
+  }
+
+  for (const auto& child : m_Children) {
+    if (child->isLosingConflict(fileIndex, fileCount)) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+bool DataItem::isOverriding(int fileIndex) const
+{
+  if (m_ConflictType == ConflictType::Ignore) {
+    return false;
+  }
+
+  if (!m_Data.isEmpty()) {
+    if (fileIndex >= m_Data.length() &&
+        m_ConflictType != ConflictType::NormalIgnoreEmpty) {
+      return m_ConflictType != ConflictType::Benign;
+    }
+
+    for (int i = 0; i < std::min(fileIndex, static_cast<int>(m_Data.length())); ++i) {
+      if (m_ConflictType == ConflictType::Benign && !m_Data[i].isValid()) {
+        continue;
+      }
+
+      if (hasConflict(m_Data[i], m_Data[fileIndex])) {
+        return true;
+      }
+    }
+  }
+
+  for (const auto& child : m_Children) {
+    if (child->isOverriding(fileIndex)) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+bool DataItem::isConflicted(int fileCount) const
+{
+  if (m_ConflictType == ConflictType::Ignore) {
+    return false;
+  }
+
+  if (!m_Data.isEmpty()) {
+    if (fileCount > m_Data.length() &&
+        m_ConflictType != ConflictType::NormalIgnoreEmpty) {
+      return true;
+    }
+
+    for (int i = 1; i < m_Data.length(); ++i) {
+      if (hasConflict(m_Data[i], m_Data[0])) {
+        return true;
+      }
+    }
+  }
+
+  for (const auto& child : m_Children) {
+    if (child->isConflicted(fileCount)) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+DataItem* DataItem::findChild(TESFile::Type signature) const
+{
+  const auto it = std::ranges::find_if(m_Children, [&](auto&& child) {
+    return child->signature() == signature;
+  });
+
+  return it != std::end(m_Children) ? it->get() : nullptr;
+}
+
+QVariant DataItem::childData(TESFile::Type signature, int fileIndex) const
+{
+  const auto it = std::ranges::find_if(m_Children, [&](auto&& child) {
+    return child->signature() == signature;
+  });
+
+  if (it == std::end(m_Children)) {
+    return QVariant();
+  }
+
+  return (*it)->data(fileIndex);
+}
+
+QVariant DataItem::childData(const QString& name, int fileIndex) const
+{
+  const auto it = std::ranges::find_if(m_Children, [&](auto&& child) {
+    return child->name() == name;
+  });
+
+  if (it == std::end(m_Children)) {
+    return QVariant();
+  }
+
+  return (*it)->data(fileIndex);
+}
+
+int DataItem::indexOf(const DataItem* child) const
+{
+  const auto it = std::ranges::find(m_Children, child, &std::shared_ptr<DataItem>::get);
+  if (it == std::end(m_Children)) {
+    return -1;
+  }
+  return std::distance(std::begin(m_Children), it);
+}
+
+DataItem* DataItem::getOrInsertChild(int index, const QString& name,
+                                     ConflictType conflictType)
+{
+  if (index < m_Children.size()) {
+    const auto& child = m_Children[index];
+    if (child->name() == name) {
+      return child.get();
+    }
+  }
+  return insertChild(index, name, conflictType);
+}
+
+DataItem* DataItem::getOrInsertChild(int index, TESFile::Type signature,
+                                     const QString& name, ConflictType conflictType)
+{
+  if (index < m_Children.size()) {
+    const auto& child = m_Children[index];
+    if (child->signature() == signature) {
+      return child.get();
+    }
+  }
+  return insertChild(index, signature, name, conflictType);
+}
+
+void DataItem::setData(int fileIndex, const QVariant& data, bool caseSensitive)
+{
+  if (m_Data.size() <= fileIndex) {
+    m_Data.resize(fileIndex + 1);
+  }
+  m_Data[fileIndex] = data;
+  m_CaseSensitive   = caseSensitive;
+}
+
+void DataItem::setDisplayData(int fileIndex, const QVariant& data)
+{
+  if (m_DisplayData.size() <= fileIndex) {
+    m_DisplayData.resize(fileIndex + 1);
+  }
+  m_DisplayData[fileIndex] = data;
+}
+
+bool DataItem::hasConflict(const QVariant& var1, const QVariant& var2) const
+{
+  if (!m_CaseSensitive && var1.userType() == QMetaType::QString &&
+      var2.userType() == QMetaType::QString) {
+    return var1.toString().compare(var2.toString(), Qt::CaseInsensitive) != 0;
+  } else {
+    return var1 != var2;
+  }
+}
+
+}  // namespace TESData