- Added mock_lseek declaration and implementation for Linux
- Added mock_SetFilePointer declaration and implementation for Windows
- Added sys_lseek and sys_SetFilePointer macros for both BUILD_TEST and production modes
- Mocks follow existing pattern: validate descriptors, check type, forward to real functions
- Both mocks properly handle error cases and set errno/SetLastError
Add mock implementation for MoveFileExW Windows API function following
the existing pattern in the codebase. The mock forwards calls to the
real Windows API, allowing for future interception in the simulation
framework if needed.
CRITICAL BUG FIX: The previous Windows implementation had a fatal flaw
where it deleted the old WAL file before renaming, creating a window
where all data could be lost if the rename failed.
Previous (BROKEN) Windows code:
remove_file_or_dir(wal->file_path); // Delete old file
rename(...); // <-- If this fails, we've lost all data!
New implementation uses MoveFileExW with MOVEFILE_REPLACE_EXISTING:
- Windows: MoveFileExW(..., MOVEFILE_REPLACE_EXISTING) atomically
replaces the destination file, matching Unix semantics
- Unix/Linux: rename() continues to atomically replace as before
- Both platforms now have atomic file replacement with no data loss window
This ensures durability on both platforms - if the operation fails at
any point, we still have either the old file or the new file, never
losing all data.
This commit addresses several important robustness issues in the WAL
implementation:
1. Fixed file_path lifetime issue:
- The file_path argument to wal_open() may not have the same lifetime
as the WAL structure
- Now allocate and copy the path string to ensure WAL owns its data
- Properly free the allocated path in wal_close()
- Added error cleanup path in wal_open() to prevent memory leaks
2. Replaced static arrays with dynamic allocation in next_entry():
- Static arrays were not thread-safe and had limited lifetimes
- Now dynamically allocate path buffer and hash buffers using sys_malloc
- Caller must free allocated fields after using the entry
- Added proper error cleanup to free allocations on failure
- Updated wal_open() to free entry fields after processing each entry
3. Improved swap_file() for cross-platform compatibility:
- On Unix/Linux: rename() atomically replaces the destination file
- On Windows: rename() doesn't overwrite, so delete old file first
- Added platform-specific handling with #ifdef _WIN32
- Ensures WAL rotation works correctly on both platforms
4. Added system.h include for sys_malloc/sys_free definitions
These changes ensure proper memory management, prevent leaks, and make
the WAL implementation more robust across different platforms.
This commit completes the Write-Ahead Log (WAL) implementation for the
metadata server, including all missing functionality and error fixes:
File System Changes (src/file_system.c):
- Implemented file_set_offset() using lseek (Linux) and SetFilePointer (Windows)
- Implemented file_get_offset() to get current file position
WAL Header Changes (src/wal.h):
- Added file_tree pointer to WAL structure for snapshot serialization
- Added file_path to WAL structure for rotation operations
WAL Implementation (src/wal.c):
- Fixed handle assignment bug in wal_open (was using wal->handle before assignment)
- Fixed missing return statement in append_begin()
- Implemented serialize_callback for writing file tree snapshots to WAL
- Implemented deserialize_callback for reading file tree snapshots from WAL
- Implemented next_entry() to read WAL entries from file during recovery
- Implemented wal_append_write() to write file modifications to WAL
- Implemented swap_file() for complete WAL file rotation:
* Creates temporary file with new snapshot
* Writes WAL header and serialized file tree
* Atomically replaces old WAL file
* Resets entry counter for new rotation cycle
- Added WAL file initialization for newly created files
- Added helper functions: read_exact, read_u8, read_u16, read_u32, read_u64, write_u32
- Fixed typo in comment (Not -> Now)
The WAL now supports:
- Full crash recovery by replaying logged operations
- Automatic file rotation when entry limit is reached
- Atomic file replacement to ensure durability
- Proper file locking throughout rotation process
Use the standard lcov tools instead of custom HTML generation.
Changes:
- Completely rewrite generate_coverage_html.sh to use lcov
- Install lcov if not available
- Use lcov to capture coverage data from .gcda files
- Use genhtml to create HTML reports with branch coverage
- Add scripts/README.md with usage instructions
Benefits:
- Professional HTML reports with standard lcov styling
- Better branch coverage visualization
- Sortable tables by line/function/branch coverage
- Source code view with execution counts
- Much simpler script (30 lines vs 200+ lines)
The reports now show:
- 32.1% branch coverage (781/2431 branches)
- 43.5% line coverage
- 61.3% function coverage
cozis
