From cf71ea8b0be8c2073bd46e88d365ad1130249524 Mon Sep 17 00:00:00 2001
From: xiepengfei <xiepengfei@uniontech.com>
Date: Wed, 16 Sep 2026 16:48:57 +0800
Subject: [PATCH] fix: add QTemporaryDir::isValid() check to prevent silent
 failure

When TMPDIR environment variable points to a non-existent directory,
QTemporaryDir construction silently fails and path() returns an empty
string. Two locations were affected:

1. DjVuDocument::save() in reader/document/DjVuModel.cpp:795
   - save() used the empty path to construct a temp file path,
     causing saveAs() to operate on an invalid path.

2. DocSheet::convertedFileDir() in reader/uiframe/DocSheet.cpp:983
   - convertedFileDir() returned the empty path to callers,
     causing subsequent file operations to silently fail.

Fix: add isValid() check after QTemporaryDir creation in both
locations. On failure, log a warning with errorString() and return
an appropriate error value (false / empty QString).
---
 reader/document/DjVuModel.cpp | 4 ++++
 reader/uiframe/DocSheet.cpp   | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/reader/document/DjVuModel.cpp b/reader/document/DjVuModel.cpp
index 5429ce7de..ffc61d85e 100644
--- a/reader/document/DjVuModel.cpp
+++ b/reader/document/DjVuModel.cpp
@@ -793,6 +793,10 @@ bool DjVuDocument::save() const
 {
     qCDebug(appLog) << "Saving document to:" << m_filePath;
     QTemporaryDir tempDir;
+    if (!tempDir.isValid()) {
+        qCWarning(appLog) << "Failed to create temporary directory:" << tempDir.errorString();
+        return false;
+    }
 
     QString tempFilePath = tempDir.path() + "/" + QUuid::createUuid().toString();
 
diff --git a/reader/uiframe/DocSheet.cpp b/reader/uiframe/DocSheet.cpp
index a07111aa9..f77831306 100644
--- a/reader/uiframe/DocSheet.cpp
+++ b/reader/uiframe/DocSheet.cpp
@@ -982,6 +982,12 @@ QString DocSheet::convertedFileDir()
     qCDebug(appLog) << "convertedFileDir";
     if (m_tempDir == nullptr)
         m_tempDir = new QTemporaryDir;
+    if (!m_tempDir->isValid()) {
+        qCWarning(appLog) << "Failed to create temporary directory:" << m_tempDir->errorString();
+        delete m_tempDir;
+        m_tempDir = nullptr;
+        return QString();
+    }
 
     qCDebug(appLog) << "临时目录: " << m_tempDir->path();
     return m_tempDir->path();