Time-Traveling File System

This is a complete implementation of an in-memory, time-traveling file system.

Interactive Build & Run:

    bash compile.sh
    ./tfs

Build & Run for Quick Testing:

• Create a file, say sample_input.txt with commands for testing.
• Build using bash compile.sh
• Run ./tfs > sample_input.txt

Project contents

• main.cpp: Command-line interface and program entry.

• tree.hpp: TreeNode structure for file versions.

• file.hpp: File class holding version tree and operations.

• filesystem.hpp: FileSystem class managing multiple files and analytics.

• hashmap.hpp: Minimal separate-chaining HashMap implemented from scratch.

• heap.hpp: BinaryMaxHeap generic max-heap.

• compile.sh: Build script. Run bash compile.sh.

• sample_input.txt: Example command sequence to try the system quickly.

Commands

See the interactive HELP inside the program for a similar list.

Major commands:

• CREATE <filename> Create a new file with root version id = 0, empty content, and an initial snapshot message ("Initial root"). Root is immutable (snapshotted at creation).

• READ <filename> Print the content of the file’s currently active version.

• INSERT <filename> <content...> Append content. If active version is a snapshot, a new child version is created with appended content. Otherwise, the active version is edited in-place.

• UPDATE <filename> <content...> Replace content. Follows the same snapshot semantics as INSERT.

• SNAPSHOT <filename> <message...> Mark the active version as a snapshot; record message and timestamp. (A snapshotted version becomes immutable.)

• ROLLBACK <filename> [versionID] If versionID is given, move the active pointer to that version. Otherwise, move to the parent of the current active version. Errors if already at root and no parent.

• HISTORY <filename> List all snapshotted versions in chronological order (by snapshot timestamp). Each line:
  version_id <epoch_seconds> <message>

• RECENT_FILES [num] List files in descending order of their last modification time. Each line:
  <filename> <epoch_seconds>

• BIGGEST_TREES [num] List files in descending order of total version count. Each line:
  <filename> <count>

• HELP Shows all the possible commands.

• EXIT Quit the program.

Semantics & Notes

• Root version (ID 0) is created as a snapshot with message Initial root.
• Snapshotted versions are immutable. Editing while the active version is snapshotted creates a child version.
• Version IDs start at 0 and increment per file.
• HISTORY prints snapshotted versions in chronological order with epoch timestamps.
• RECENT_FILES and BIGGEST_TREES accept an optional numeric argument to limit results.
• Errors print as ERROR: ....