set file size in linux if needed

2026-08-28 01:14:02 +02:00
parent 9ae55ac60f
commit e51afcbdf5
1 changed files with 8 additions and 3 deletions
@@ -148,9 +148,14 @@ WritableMemoryMappedFile::WritableMemoryMappedFile(const File& p_file, const std
    m_fileDescriptor = open(path.data(), O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
    CRITICAL_ASSERT(SystemAssertHandler, m_fileDescriptor != -1, "Failed to create file {}", path);

-    [[maybe_unused]]
-    const int truncateResult = ftruncate(m_fileDescriptor, static_cast<off_t>(p_size));
-    CRITICAL_ASSERT(SystemAssertHandler, truncateResult == 0, "Failed to size file {}", path);
+    struct stat fileStat {};
+    fstat(m_fileDescriptor, &fileStat);
+    if (static_cast<std::size_t>(fileStat.st_size) < p_size)
+    {
+        [[maybe_unused]]
+        const int truncateResult = ftruncate(m_fileDescriptor, static_cast<off_t>(p_size));
+        CRITICAL_ASSERT(SystemAssertHandler, truncateResult == 0, "Failed to size file {}", path);
+    }

    void* const mapped = mmap(nullptr, m_size, PROT_READ | PROT_WRITE, MAP_SHARED, m_fileDescriptor, 0);
    CRITICAL_ASSERT(SystemAssertHandler, mapped != MAP_FAILED, "Failed to map file {}", path);