Command-line tool and zsh plugin for ranking and suggesting recently visited directories by frecency.

Has a frontend that uses Rofi:

Licenced under CC0 - but be warned - TDB, which this depends on, is licensed under LGPL.

Since this is a work-in-extremely-slow progress and rather quirky, I put the (likely non-exhaustive) limitations section first, to avoid wasting other developers time.

• Only Rofi support. This is extendable, via zstyle configuration, but only a Rofi frontend exists now. Note: Since Rofi is a graphical program, this prevents the program from working over SSH.
• This has only ever been compiled and run on Arch Linux, and only by me (at least at the time of writing). Thus, it has plenty of bugs for others to find.
• Currently, this only compiles on Clang with the LLD linker. This has little to do with actual requirements, it is a side effect of trying to squeeze the executable as small as possible. (The executable is 23kB, but the size saving is obviously not worth forcing a specific compiler or having to maintain separate configurations for various toolchains)
• Only knows about directories - i.e. there is no support for tracking most frecently run programs. I might add it some day but no promises.
• No installer / packaging - you're stuck with copying files manually.

Written in C (C2X), using TDB as the database. Requires Clang and lld, due to optimizing for the sake of optimization.

The database structure consists of four queues that each contain entries for frecently visited directories. Every time a directory is visited, it gets a queue-specific constant added to its frecency. And when time passes, the frecencies of directories decay exponentially - and with a different half-life in each queue. Thus, if you only visit a directory once, it will jump to the top of the fastest queue and will show in your history search instantly - but the other queues tend to favor frequency over recency. so the oft-visited directories will stay in the list even though they haven't been used in a while, but the recently but only once used directory will disappear in about an hour.

The database consists of a single file (in ~/.local/share/hist/db.tdb), managed with the TDB library. This supports simultaneoius access on a local machine, since TDB uses transactions. TDB's file-based locking is used instead of the newer locking mechanism based on shared Mutexes. This is because the command-line program only does a small task to write or read the database and exits - the runtime check for robust mutex support in TDB would spawn subprocesses to verify that the mutexes work. This would invariably take more time than the actual task in this case.

Since losing the directory recommendations would only be a mild inconvenience, syncing the transactions to disk is disabled. Thus, power failure could easily crash the database - but it will not randomly crash due to concurrent access. So far, it's been uncrashed much longer than the various SQLite based history recommenders I've tried.

0. Clone this repository.

1. Install dependenciese:

   • clang,
   • lld (LLVM's linker - this might come with Clang on some distributions).
   • meson and ninja,
   • tdb
   • xxhash
   • rofi

2. Create a build directory under the repository root, and enter it: mkdir build cd build

3. Run Meson with clang set as its default compiler:

   # In the build directory:
   env CC=clang meson ..
   

4. Build with Ninja:

   # In the build directory:
   ninja
   

5. Assuming that you want to keep the compilation artifacts in the build dir (there is no packaging yet), add configuration to your .zshrc:

   source "$HOME/hist/_show_rofi.zsh"
   source "$HOME/hist/hist.zsh"
   
   # To change the menu from the default Rofi, you the frontend
   # can be set to whatever command here. The output is not a simple
   # DMenu though - at least disable the markup option to avoid having
   # to deal with Pango markup.
   zstyle ':hist:*' menu "rofi_select --markup --prompt Cd:"
   zstyle ':hist:*' markup 1
   # Ignore the home directory - it would likely show on the top every time
   zstyle ':hist' ignored_dirs "$HOME"
   # Shorten /home/YOUR-NAME-HERE/ to ~/
   zstyle ':hist:*' shorten_home 1
   
   # Bind the history selector to some key (here bound to Ctrl-G):
   bindkey "^[G" hist-cd
   

6. See what breaks, and open issues or pull requests!