A failing spec'd out bitcask, a start of something fun :)

.gitignore

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+zig-cache/
+zig-out/
+/release/
+/debug/
+/build/
+/build-*/
+/docgen_tmp/

README.md

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+# Bitcask - A Simple KV datastore
+
+Do it simply and do it well.
+
+## The Bitcask paper
+
+https://riak.com/assets/bitcask-intro.pdf

build.zig

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+const std = @import("std");
+
+pub fn build(b: *std.build.Builder) void {
+    // Standard target options allows the person running `zig build` to choose
+    // what target to build for. Here we do not override the defaults, which
+    // means any target is allowed, and the default is native. Other options
+    // for restricting supported target set are available.
+    const target = b.standardTargetOptions(.{});
+
+    // Standard release options allow the person running `zig build` to select
+    // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall.
+    const mode = b.standardReleaseOptions();
+
+    const exe = b.addExecutable("bitcask", "src/main.zig");
+    exe.setTarget(target);
+    exe.setBuildMode(mode);
+    exe.install();
+
+    const run_cmd = exe.run();
+    run_cmd.step.dependOn(b.getInstallStep());
+    if (b.args) |args| {
+        run_cmd.addArgs(args);
+    }
+
+    const run_step = b.step("run", "Run the app");
+    run_step.dependOn(&run_cmd.step);
+
+    const exe_tests = b.addTest("src/main.zig");
+    exe_tests.setTarget(target);
+    exe_tests.setBuildMode(mode);
+
+    const test_step = b.step("test", "Run unit tests");
+    test_step.dependOn(&exe_tests.step);
+}

src/Bitcask/bitcask.zig

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+const std = @import("std");
+const expect = std.testing.expect;
+
+pub const BitcaskFileError = error{
+    AccessDenied,
+    OutOfMemory,
+    FileNotFound,
+};
+
+pub const BitCask = struct {
+    const FILE_THRESHOLD_SIZE = 1000;
+
+
+    // std.StringArrayHashMap
+
+    // From the Bitcask paper, the API should look something like this
+
+    //** TODO
+
+    // What is the BitcaskHandel? How can I represent it?
+    // Implement opening and closing files
+    // Impement the spec
+
+    // ***
+
+
+    // bitcask:open(DirectoryName, Opts) Open a new or existing Bitcask datastore with additional options.
+    // → BitCaskHandle | {error, any()} Valid options include read write (if this process is going to be a
+    // writer and not just a reader) and sync on put (if this writer would
+    // prefer to sync the write file after every write operation).
+    // The directory must be readable and writable by this process, and
+    // only one process may open a Bitcask with read write at a time.
+    // bitcask:open(DirectoryName) Open a new or existing Bitcask datastore for read-only access.
+    // → BitCaskHandle | {error, any()} The directory and all files in it must be readable by this process.
+    fn open(directory_name: []const u8) BitcaskFileError!void {
+        std.debug.print("Opening bitcask in dir {s}\n", .{directory_name});
+        return error.FileNotFound;
+    }
+
+    // bitcask:get(BitCaskHandle, Key) Retrieve a value by key from a Bitcask datastore.
+    // → not found | {ok, Value}
+    fn get(key: []const u8) error{NotImplemented}!void {
+        std.debug.print("Getting value with key {s}\n", .{key});
+        return error.NotImplemented;
+    }
+
+    // bitcask:put(BitCaskHandle, Key, Value) Store a key and value in a Bitcask datastore.
+    // → ok | {error, any()}
+    fn put() error{NotImplemented}!void {
+        return error.NotImplemented;
+    }
+
+    // bitcask:delete(BitCaskHandle, Key) Delete a key from a Bitcask datastore.
+    // → ok | {error, any()}
+    fn delete() error{NotImplemented}!void {
+        return error.NotImplemented;
+    }
+
+    // bitcask:list keys(BitCaskHandle) List all keys in a Bitcask datastore.
+    // → [Key] | {error, any()}
+    fn list() error{NotImplemented}!void {
+        return error.NotImplemented;
+    }
+
+    // bitcask:fold(BitCaskHandle,Fun,Acc0) Fold over all K/V pairs in a Bitcask datastore.
+    // → Acc Fun is expected to be of the form: F(K,V,Acc0) → Acc.
+    fn fold() error{NotImplemented}!void {
+        return error.NotImplemented;
+    }
+
+    // bitcask:merge(DirectoryName) Merge several data files within a Bitcask datastore into a more
+    // → ok | {error, any()} compact form. Also, produce hintfiles for faster startup.
+    fn merge() error{NotImplemented}!void {
+        return error.NotImplemented;
+    }
+
+    // bitcask:sync(BitCaskHandle) Force any writes to sync to disk.
+    // → ok
+    fn sync() error{NotImplemented}!void {
+        return error.NotImplemented;
+    }
+
+    // bitcask:close(BitCaskHandle) Close a Bitcask data store and flush all pending writes (if any) to disk
+    fn close() error{NotImplemented}!void {
+        return error.NotImplemented;
+    }
+};
+
+test "Bitcask spec implementation: open" {
+    const bc = BitCask;
+    try bc.open("File");
+    // bc.open("File") catch |err| {
+    //     try expect(err == error.FileNotFound);
+    // };
+
+}
+
+test "Bitcask spec implementation: get" {
+    const bc = BitCask;
+    try bc.get("key");
+}
+
+test "Bitcask spec implementation: put" {
+    const bc = BitCask;
+    try bc.put();
+}
+
+test "Bitcask spec implementation: delete" {
+    const bc = BitCask;
+    try bc.delete();
+}
+
+test "Bitcask spec implementation: list" {
+    const bc = BitCask;
+    try bc.list();
+}
+
+test "Bitcask spec implementation: fold" {
+    const bc = BitCask;
+    try bc.fold();
+}
+
+test "Bitcask spec implementation: merge" {
+    const bc = BitCask;
+    try bc.merge();
+}
+
+test "Bitcask spec implementation: sync" {
+    const bc = BitCask;
+    try bc.merge();
+}
+
+test "Bitcask spec implementation: close" {
+    const bc = BitCask;
+    try bc.close();
+}

src/main.zig

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+const std = @import("std");
+
+pub fn main() !void {
+    // Prints to stderr (it's a shortcut based on `std.io.getStdErr()`)
+    std.debug.print("All your {s} are belong to us.\n", .{"codebase"});
+
+    // stdout is for the actual output of your application, for example if you
+    // are implementing gzip, then only the compressed bytes should be sent to
+    // stdout, not any debugging messages.
+    const stdout_file = std.io.getStdOut().writer();
+    var bw = std.io.bufferedWriter(stdout_file);
+    const stdout = bw.writer();
+
+    try stdout.print("Run `zig build test` to run the tests.\n", .{});
+
+    try bw.flush(); // don't forget to flush!
+}
+
+test "simple test" {
+    var list = std.ArrayList(i32).init(std.testing.allocator);
+    defer list.deinit(); // try commenting this out and see if zig detects the memory leak!
+    try list.append(42);
+    try std.testing.expectEqual(@as(i32, 42), list.pop());
+}