6 files changed, 79 insertions, 25 deletions

diff --git a/src/common/fs/file.cpp b/src/common/fs/file.cpp
index 710e88b39..274f57659 100644
--- a/src/common/fs/file.cpp
+++ b/src/common/fs/file.cpp
@@ -172,7 +172,7 @@ std::string ReadStringFromFile(const std::filesystem::path& path, FileType type)
 
 size_t WriteStringToFile(const std::filesystem::path& path, FileType type,
                          std::string_view string) {
-    if (!IsFile(path)) {
+    if (Exists(path) && !IsFile(path)) {
         return 0;
     }
 
@@ -183,7 +183,7 @@ size_t WriteStringToFile(const std::filesystem::path& path, FileType type,
 
 size_t AppendStringToFile(const std::filesystem::path& path, FileType type,
                           std::string_view string) {
-    if (!IsFile(path)) {
+    if (Exists(path) && !IsFile(path)) {
         return 0;
     }
 
@@ -306,9 +306,9 @@ bool IOFile::Flush() const {
     errno = 0;
 
 #ifdef _WIN32
-    const auto flush_result = std::fflush(file) == 0 && _commit(fileno(file)) == 0;
+    const auto flush_result = std::fflush(file) == 0;
 #else
-    const auto flush_result = std::fflush(file) == 0 && fsync(fileno(file)) == 0;
+    const auto flush_result = std::fflush(file) == 0;
 #endif
 
     if (!flush_result) {
@@ -320,6 +320,28 @@ bool IOFile::Flush() const {
     return flush_result;
 }
 
+bool IOFile::Commit() const {
+    if (!IsOpen()) {
+        return false;
+    }
+
+    errno = 0;
+
+#ifdef _WIN32
+    const auto commit_result = std::fflush(file) == 0 && _commit(fileno(file)) == 0;
+#else
+    const auto commit_result = std::fflush(file) == 0 && fsync(fileno(file)) == 0;
+#endif
+
+    if (!commit_result) {
+        const auto ec = std::error_code{errno, std::generic_category()};
+        LOG_ERROR(Common_Filesystem, "Failed to commit the file at path={}, ec_message={}",
+                  PathToUTF8String(file_path), ec.message());
+    }
+
+    return commit_result;
+}
+
 bool IOFile::SetSize(u64 size) const {
     if (!IsOpen()) {
         return false;
@@ -347,6 +369,9 @@ u64 IOFile::GetSize() const {
         return 0;
     }
 
+    // Flush any unwritten buffered data into the file prior to retrieving the file size.
+    std::fflush(file);
+
     std::error_code ec;
 
     const auto file_size = fs::file_size(file_path, ec);
diff --git a/src/common/fs/file.h b/src/common/fs/file.h
index 0f10b6003..2c4ab4332 100644
--- a/src/common/fs/file.h
+++ b/src/common/fs/file.h
@@ -49,7 +49,7 @@ void OpenFileStream(FileStream& file_stream, const Path& path, std::ios_base::op
 
 /**
  * Reads an entire file at path and returns a string of the contents read from the file.
- * If the filesystem object at path is not a file, this function returns an empty string.
+ * If the filesystem object at path is not a regular file, this function returns an empty string.
  *
  * @param path Filesystem path
  * @param type File type
@@ -72,7 +72,8 @@ template <typename Path>
 /**
  * Writes a string to a file at path and returns the number of characters successfully written.
  * If a file already exists at path, its contents will be erased.
- * If the filesystem object at path is not a file, this function returns 0.
+ * If a file does not exist at path, it creates and opens a new empty file for writing.
+ * If the filesystem object at path exists and is not a regular file, this function returns 0.
  *
  * @param path Filesystem path
  * @param type File type
@@ -95,7 +96,8 @@ template <typename Path>
 
 /**
  * Appends a string to a file at path and returns the number of characters successfully written.
- * If the filesystem object at path is not a file, this function returns 0.
+ * If a file does not exist at path, it creates and opens a new empty file for appending.
+ * If the filesystem object at path exists and is not a regular file, this function returns 0.
  *
  * @param path Filesystem path
  * @param type File type
@@ -394,11 +396,20 @@ public:
     [[nodiscard]] size_t WriteString(std::span<const char> string) const;
 
     /**
-     * Flushes any unwritten buffered data into the file.
+     * Attempts to flush any unwritten buffered data into the file.
      *
      * @returns True if the flush was successful, false otherwise.
      */
-    [[nodiscard]] bool Flush() const;
+    bool Flush() const;
+
+    /**
+     * Attempts to commit the file into the disk.
+     * Note that this is an expensive operation as this forces the operating system to write
+     * the contents of the file associated with the file descriptor into the disk.
+     *
+     * @returns True if the commit was successful, false otherwise.
+     */
+    bool Commit() const;
 
     /**
      * Resizes the file to a given size.
diff --git a/src/common/fs/fs.cpp b/src/common/fs/fs.cpp
index d3159e908..9089cad67 100644
--- a/src/common/fs/fs.cpp
+++ b/src/common/fs/fs.cpp
@@ -135,8 +135,9 @@ std::shared_ptr<IOFile> FileOpen(const fs::path& path, FileAccessMode mode, File
         return nullptr;
     }
 
-    if (!IsFile(path)) {
-        LOG_ERROR(Common_Filesystem, "Filesystem object at path={} is not a file",
+    if (Exists(path) && !IsFile(path)) {
+        LOG_ERROR(Common_Filesystem,
+                  "Filesystem object at path={} exists and is not a regular file",
                   PathToUTF8String(path));
         return nullptr;
     }
diff --git a/src/common/fs/fs.h b/src/common/fs/fs.h
index f6f256349..183126de3 100644
--- a/src/common/fs/fs.h
+++ b/src/common/fs/fs.h
@@ -48,18 +48,18 @@ template <typename Path>
  *
  * Failures occur when:
  * - Input path is not valid
- * - Filesystem object at path is not a file
+ * - Filesystem object at path is not a regular file
  * - Filesystem at path is read only
  *
  * @param path Filesystem path
  *
  * @returns True if file removal succeeds or file does not exist, false otherwise.
  */
-[[nodiscard]] bool RemoveFile(const std::filesystem::path& path);
+bool RemoveFile(const std::filesystem::path& path);
 
 #ifdef _WIN32
 template <typename Path>
-[[nodiscard]] bool RemoveFile(const Path& path) {
+bool RemoveFile(const Path& path) {
     if constexpr (IsChar<typename Path::value_type>) {
         return RemoveFile(ToU8String(path));
     } else {
@@ -74,7 +74,7 @@ template <typename Path>
  * Failures occur when:
  * - One or both input path(s) is not valid
  * - Filesystem object at old_path does not exist
- * - Filesystem object at old_path is not a file
+ * - Filesystem object at old_path is not a regular file
  * - Filesystem object at new_path exists
  * - Filesystem at either path is read only
  *
@@ -110,8 +110,8 @@ template <typename Path1, typename Path2>
  *
  * Failures occur when:
  * - Input path is not valid
- * - Filesystem object at path is not a file
- * - The file is not opened
+ * - Filesystem object at path exists and is not a regular file
+ * - The file is not open
  *
  * @param path Filesystem path
  * @param mode File access mode
@@ -251,11 +251,11 @@ template <typename Path>
  *
  * @returns True if directory removal succeeds or directory does not exist, false otherwise.
  */
-[[nodiscard]] bool RemoveDir(const std::filesystem::path& path);
+bool RemoveDir(const std::filesystem::path& path);
 
 #ifdef _WIN32
 template <typename Path>
-[[nodiscard]] bool RemoveDir(const Path& path) {
+bool RemoveDir(const Path& path) {
     if constexpr (IsChar<typename Path::value_type>) {
         return RemoveDir(ToU8String(path));
     } else {
@@ -276,11 +276,11 @@ template <typename Path>
  *
  * @returns True if the directory and all of its contents are removed successfully, false otherwise.
  */
-[[nodiscard]] bool RemoveDirRecursively(const std::filesystem::path& path);
+bool RemoveDirRecursively(const std::filesystem::path& path);
 
 #ifdef _WIN32
 template <typename Path>
-[[nodiscard]] bool RemoveDirRecursively(const Path& path) {
+bool RemoveDirRecursively(const Path& path) {
     if constexpr (IsChar<typename Path::value_type>) {
         return RemoveDirRecursively(ToU8String(path));
     } else {
@@ -301,11 +301,11 @@ template <typename Path>
  *
  * @returns True if all of the directory's contents are removed successfully, false otherwise.
  */
-[[nodiscard]] bool RemoveDirContentsRecursively(const std::filesystem::path& path);
+bool RemoveDirContentsRecursively(const std::filesystem::path& path);
 
 #ifdef _WIN32
 template <typename Path>
-[[nodiscard]] bool RemoveDirContentsRecursively(const Path& path) {
+bool RemoveDirContentsRecursively(const Path& path) {
     if constexpr (IsChar<typename Path::value_type>) {
         return RemoveDirContentsRecursively(ToU8String(path));
     } else {
@@ -435,11 +435,13 @@ template <typename Path>
 #endif
 
 /**
- * Returns whether a filesystem object at path is a file.
+ * Returns whether a filesystem object at path is a regular file.
+ * A regular file is a file that stores text or binary data.
+ * It is not a directory, symlink, FIFO, socket, block device, or character device.
  *
  * @param path Filesystem path
  *
- * @returns True if a filesystem object at path is a file, false otherwise.
+ * @returns True if a filesystem object at path is a regular file, false otherwise.
  */
 [[nodiscard]] bool IsFile(const std::filesystem::path& path);
 
diff --git a/src/common/fs/fs_util.cpp b/src/common/fs/fs_util.cpp
index 357cf5855..9f8671982 100644
--- a/src/common/fs/fs_util.cpp
+++ b/src/common/fs/fs_util.cpp
@@ -20,6 +20,10 @@ std::string ToUTF8String(std::u8string_view u8_string) {
     return std::string{u8_string.begin(), u8_string.end()};
 }
 
+std::string BufferToUTF8String(std::span<const u8> buffer) {
+    return std::string{buffer.begin(), std::ranges::find(buffer, u8{0})};
+}
+
 std::string PathToUTF8String(const std::filesystem::path& path) {
     return ToUTF8String(path.u8string());
 }
diff --git a/src/common/fs/fs_util.h b/src/common/fs/fs_util.h
index ec9950ee7..1ec82eb35 100644
--- a/src/common/fs/fs_util.h
+++ b/src/common/fs/fs_util.h
@@ -47,6 +47,17 @@ concept IsChar = std::same_as<T, char>;
 [[nodiscard]] std::string ToUTF8String(std::u8string_view u8_string);
 
 /**
+ * Converts a buffer of bytes to a UTF8-encoded std::string.
+ * This converts from the start of the buffer until the first encountered null-terminator.
+ * If no null-terminator is found, this converts the entire buffer instead.
+ *
+ * @param buffer Buffer of bytes
+ *
+ * @returns UTF-8 encoded std::string.
+ */
+[[nodiscard]] std::string BufferToUTF8String(std::span<const u8> buffer);
+
+/**
  * Converts a filesystem path to a UTF-8 encoded std::string.
  *
  * @param path Filesystem path