Simple KV store testing HashMap in Zig

1 files changed, 94 insertions, 0 deletions

diff --git a/zig-kv-store/main.zig b/zig-kv-store/main.zig
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+++ b/zig-kv-store/main.zig
@@ -0,0 +1,94 @@
+// https://github.com/memcached/memcached/wiki/Commands
+// https://ziglang.org/documentation/master/std/#std.hash_map.HashMap
+
+const std = @import("std");
+
+const Error = error{
+    Failed,
+    KeyNotFound,
+};
+
+const Store = struct {
+    data: std.StringHashMap([]const u8),
+
+    pub fn set(self: *Store, key: []const u8, value: []const u8) !void {
+        self.data.put(key, value) catch |err| {
+            std.log.err("Failed adding key `{s}` with error {}", .{ key, err });
+            return error.Failed;
+        };
+    }
+
+    pub fn get(self: *Store, key: []const u8) ![]const u8 {
+        if (self.data.get(key)) |value| {
+            return value;
+        }
+        return error.KeyNotFound;
+    }
+
+    pub fn del(self: *Store, key: []const u8) !void {
+        if (!self.data.remove(key)) {
+            std.log.err("Failed deleting key `{s}`", .{key});
+            return error.KeyNotFound;
+        }
+    }
+};
+
+pub fn main() !void {
+    var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
+    defer arena.deinit();
+    var allocator = arena.allocator();
+
+    var store = Store{ .data = std.StringHashMap([]const u8).init(allocator) };
+    defer store.data.deinit();
+
+    // Setting new key.
+    {
+        const key = "johhny";
+        try store.set(key, "blaze");
+    }
+
+    // Retrieving back existing key if we know it will never return an error.
+    {
+        const key = "johhny";
+        const result = store.get(key) catch unreachable;
+        std.log.info("Value: {s}", .{result});
+    }
+
+    // Retrieving back the value and handling errors.
+    {
+        const key = "unknown";
+        if (store.get(key)) |val| {
+            std.log.info("Value: {s}", .{val});
+        } else |err| {
+            std.log.err("Error: {any}", .{err});
+        }
+    }
+
+    // Retrieving back key that does not exist and handling specific errors.
+    {
+        const key = "unknown";
+        if (store.get(key)) |val| {
+            std.log.info("Value: {s}", .{val});
+        } else |err| switch (err) {
+            error.KeyNotFound => {
+                std.log.err("Key `{s}` was not found", .{key});
+            },
+        }
+    }
+
+    // Deleting existing key.
+    {
+        const key = "johhny";
+        try store.del(key);
+    }
+
+    // Retrieving back the value and handling errors.
+    {
+        const key = "johnny";
+        if (store.get(key)) |val| {
+            std.log.info("Value: {s}", .{val});
+        } else |err| {
+            std.log.err("Error: {any}", .{err});
+        }
+    }
+}