Stub out account creation

src/db.zig

@@ -1,59 +1,120 @@
 const std = @import("std");
-const root = @import("root");
-const Uuid = root.util.Uuid;
+const util = @import("./util.zig");
+const Uuid = util.Uuid;
+const ciutf8 = util.ciutf8;
+const assert = std.debug.assert;
 
-pub const Actor = struct {
+pub const Account = struct {
     id: Uuid,
-    display_name: ?[]const u8 = null,
     handle: []const u8,
-    host: []const u8,
-    bio: ?[]const u8 = null,
 };
 
-pub const Note = struct {
-    id: Uuid,
-    author: Uuid,
-    content: []const u8 = "",
-};
+const IdSource = struct {
+    data: *anyopaque,
+    nextFn: fn (*anyopaque) Uuid,
 
-pub fn CreateInfo(comptime T: type) type {
-    if (@typeInfo(T) != .Struct) @compileError("type is not struct");
-    if (!std.meta.trait.hasField("id")(T)) @compileError("type does not have id field");
-    if (@typeInfo(T).Struct.is_tuple) @compileError("type cannot be tuple");
+    pub fn init(pointer: anytype, comptime nextFn: fn (ptr: @TypeOf(pointer)) Uuid) IdSource {
+        const Ptr = @TypeOf(pointer);
+        assert(@typeInfo(Ptr) == .Pointer); // Must be a pointer
+        assert(@typeInfo(Ptr).Pointer.size == .One); // Must be a single-item pointer
+        assert(@typeInfo(@typeInfo(Ptr).Pointer.child) == .Struct); // Must point to a struct
+        const gen = struct {
+            fn next(ptr: *anyopaque) Uuid {
+                const alignment = @typeInfo(Ptr).Pointer.alignment;
+                const self = @ptrCast(Ptr, @alignCast(alignment, ptr));
+                return nextFn(self);
+            }
+        };
 
-    var fields: [std.meta.fields(T).len - 1]std.builtin.TypeInfo.StructField = undefined;
-    var i = 0;
-
-    for (std.meta.fields(T)) |field| {
-        if (std.mem.eql(u8, field.name, "id")) continue;
-        fields[i] = field;
-        i += 1;
+        return .{
+            .data = pointer,
+            .nextFn = gen.next,
+        };
     }
 
-    return @Type(.{
-        .Struct = .{
-            .layout = @typeInfo(T).Struct.layout,
-            .fields = &fields,
-            .is_tuple = false,
-            .decls = &[_]std.builtin.TypeInfo.Declaration{},
-        },
-    });
-}
-
-const this_host = "localhost:8080";
-
-const actor = Actor{
-    .id = Uuid.parse("f75f5160-12d3-42c2-a81d-ad2245b7a74b") catch unreachable,
-    .handle = "testacct",
-    .host = this_host,
+    fn next(self: *IdSource) Uuid {
+        return self.nextFn(self.data);
+    }
 };
 
-pub fn getActorById(id: Uuid) !?Actor {
-    if (Uuid.eql(id, actor.id)) return actor;
+const ConstId = struct {
+    val: Uuid = Uuid.Nil,
+    fn next(self: *ConstId) Uuid {
+        return self.val;
+    }
 
-    return null;
-}
+    fn source(self: *ConstId) IdSource {
+        return IdSource.init(self, next);
+    }
+};
 
-pub fn createNote(_: CreateInfo(Note)) !Uuid {
-    return Uuid.randV4(root.util.getRandom());
+pub const MemoryDb = struct {
+    const Self = @This();
+    const Table = std.ArrayListUnmanaged;
+
+    allocator: std.mem.Allocator,
+    id_source: IdSource,
+
+    accounts: Table(Account),
+
+    pub fn init(allocator: std.mem.Allocator, id_source: IdSource) Self {
+        return .{
+            .allocator = allocator,
+            .id_source = id_source,
+            .accounts = Table(Account){},
+        };
+    }
+
+    pub fn deinit(self: *Self) void {
+        self.accounts.deinit(self.allocator);
+    }
+
+    pub fn createAccount(self: *Self, handle: []const u8) !Account {
+        const id = self.id_source.next();
+
+        for (self.accounts.items) |a| {
+            if (ciutf8.eql(handle, a.handle)) {
+                return error.DuplicateHandle;
+            }
+
+            if (Uuid.eql(id, a.id)) {
+                return error.DuplicateId;
+            }
+        }
+
+        const acc = .{
+            .id = id,
+            .handle = handle,
+        };
+
+        try self.accounts.append(self.allocator, acc);
+
+        return acc;
+    }
+};
+
+test "createAccount" {
+    var next_id = ConstId{};
+    var db = MemoryDb.init(std.testing.allocator, next_id.source());
+    defer db.deinit();
+
+    const admin_id = try Uuid.parse("00000000-ffff-0000-0000-000000000000");
+    const sally_id = try Uuid.parse("00000000-eeee-0000-0000-000000000000");
+    const other_id = try Uuid.parse("00000000-dddd-0000-0000-000000000000");
+
+    next_id.val = admin_id;
+    const admin = try db.createAccount("admin");
+    try std.testing.expectEqual(admin_id, admin.id);
+    try std.testing.expectEqualStrings("admin", admin.handle);
+
+    next_id.val = other_id;
+    try std.testing.expectError(error.DuplicateHandle, db.createAccount("admin"));
+
+    next_id.val = sally_id;
+    const sally = try db.createAccount("sally");
+    try std.testing.expectEqual(sally_id, sally.id);
+    try std.testing.expectEqualStrings("sally", sally.handle);
+
+    next_id.val = admin_id;
+    try std.testing.expectError(error.DuplicateId, db.createAccount("jaina"));
 }