storage: first implementation of webstorage API

src/storage/storage.zig

@@ -0,0 +1,214 @@
+const std = @import("std");
+
+const jsruntime = @import("jsruntime");
+const Case = jsruntime.test_utils.Case;
+const checkCases = jsruntime.test_utils.checkCases;
+const generate = @import("../generate.zig");
+
+const DOMError = @import("../netsurf.zig").DOMError;
+
+const log = std.log.scoped(.storage);
+
+pub const Interfaces = generate.Tuple(.{
+    Bottle,
+});
+
+// See https://storage.spec.whatwg.org/#model for storage hierarchy.
+// A Shed contains map of Shelves. The key is the document's origin.
+// A Shelf contains on default Bucket (it could contain many in the future).
+// A Bucket contains a local and a session Bottle.
+// A Bottle stores a map of strings and is exposed to the JS.
+
+pub const Shed = struct {
+    const Map = std.StringHashMapUnmanaged(Shelf);
+
+    alloc: std.mem.Allocator,
+    map: Map,
+
+    pub fn init(alloc: std.mem.Allocator) Shed {
+        return .{
+            .alloc = alloc,
+            .map = .{},
+        };
+    }
+
+    pub fn deinit(self: *Shed) void {
+        // loop hover each KV and free the memory.
+        var it = self.map.iterator();
+        while (it.next()) |entry| {
+            entry.value_ptr.deinit();
+            self.alloc.free(entry.key_ptr.*);
+        }
+        self.map.deinit(self.alloc);
+    }
+
+    pub fn getOrPut(self: *Shed, origin: []const u8) !*Shelf {
+        const shelf = self.map.getPtr(origin);
+        if (shelf) |s| return s;
+
+        const oorigin = try self.alloc.dupe(u8, origin);
+        try self.map.put(self.alloc, oorigin, Shelf.init(self.alloc));
+        return self.map.getPtr(origin).?;
+    }
+};
+
+pub const Shelf = struct {
+    bucket: Bucket,
+
+    pub fn init(alloc: std.mem.Allocator) Shelf {
+        return .{ .bucket = Bucket.init(alloc) };
+    }
+
+    pub fn deinit(self: *Shelf) void {
+        self.bucket.deinit();
+    }
+};
+
+pub const Bucket = struct {
+    local: Bottle,
+    session: Bottle,
+
+    pub fn init(alloc: std.mem.Allocator) Bucket {
+        return .{
+            .local = Bottle.init(alloc),
+            .session = Bottle.init(alloc),
+        };
+    }
+
+    pub fn deinit(self: *Bucket) void {
+        self.local.deinit();
+        self.session.deinit();
+    }
+};
+
+// https://html.spec.whatwg.org/multipage/webstorage.html#the-storage-interface
+pub const Bottle = struct {
+    pub const mem_guarantied = true;
+    const Map = std.StringHashMapUnmanaged([]const u8);
+
+    // allocator is stored. we don't use the JS env allocator b/c the storage
+    // data could exists longer than a js env lifetime.
+    alloc: std.mem.Allocator,
+    map: Map,
+
+    pub fn init(alloc: std.mem.Allocator) Bottle {
+        return .{
+            .alloc = alloc,
+            .map = .{},
+        };
+    }
+
+    // loop hover each KV and free the memory.
+    fn free(self: *Bottle) void {
+        var it = self.map.iterator();
+        while (it.next()) |entry| {
+            self.alloc.free(entry.key_ptr.*);
+            self.alloc.free(entry.value_ptr.*);
+        }
+    }
+
+    pub fn deinit(self: *Bottle) void {
+        self.free();
+        self.map.deinit(self.alloc);
+    }
+
+    pub fn get_length(self: *Bottle) u32 {
+        return @intCast(self.map.count());
+    }
+
+    pub fn _key(self: *Bottle, idx: u32) ?[]const u8 {
+        if (idx >= self.map.count()) return null;
+
+        var it = self.map.valueIterator();
+        var i: u32 = 0;
+        while (it.next()) |v| {
+            if (i == idx) return v.*;
+            i += 1;
+        }
+        unreachable;
+    }
+
+    pub fn _getItem(self: *Bottle, k: []const u8) ?[]const u8 {
+        return self.map.get(k);
+    }
+
+    pub fn _setItem(self: *Bottle, k: []const u8, v: []const u8) !void {
+        const old = self.map.get(k);
+        if (old != null and std.mem.eql(u8, v, old.?)) return;
+
+        // owns k and v by copying them.
+        const kk = try self.alloc.dupe(u8, k);
+        errdefer self.alloc.free(kk);
+        const vv = try self.alloc.dupe(u8, v);
+        errdefer self.alloc.free(vv);
+
+        self.map.put(self.alloc, kk, vv) catch |e| {
+            log.debug("set item: {any}", .{e});
+            return DOMError.QuotaExceeded;
+        };
+
+        // TODO dispatch event
+        // > Broadcast this with key, oldValue, and value.
+        // https://html.spec.whatwg.org/multipage/webstorage.html#the-storageevent-interface
+    }
+
+    pub fn _removeItem(self: *Bottle, k: []const u8) !void {
+        const old = self.map.fetchRemove(k);
+        if (old == null) return;
+
+        // TODO dispatch event
+        // > Broadcast this with key, oldValue, and null.
+        // https://html.spec.whatwg.org/multipage/webstorage.html#the-storageevent-interface
+    }
+
+    pub fn _clear(self: *Bottle) void {
+        self.free();
+        self.map.clearRetainingCapacity();
+
+        // TODO dispatch event
+        // > Broadcast this with null, null, and null.
+        // https://html.spec.whatwg.org/multipage/webstorage.html#the-storageevent-interface
+    }
+};
+
+// Tests
+// -----
+
+pub fn testExecFn(
+    _: std.mem.Allocator,
+    js_env: *jsruntime.Env,
+) anyerror!void {
+    var storage = [_]Case{
+        .{ .src = "localStorage.length", .ex = "0" },
+
+        .{ .src = "localStorage.setItem('foo', 'bar')", .ex = "undefined" },
+        .{ .src = "localStorage.length", .ex = "1" },
+        .{ .src = "localStorage.getItem('foo')", .ex = "bar" },
+        .{ .src = "localStorage.removeItem('foo')", .ex = "undefined" },
+        .{ .src = "localStorage.length", .ex = "0" },
+
+        // .{ .src = "localStorage['foo'] = 'bar'", .ex = "undefined" },
+        // .{ .src = "localStorage['foo']", .ex = "bar" },
+        // .{ .src = "localStorage.length", .ex = "1" },
+
+        .{ .src = "localStorage.clear()", .ex = "undefined" },
+        .{ .src = "localStorage.length", .ex = "0" },
+    };
+    try checkCases(js_env, &storage);
+}
+
+test "storage bottle" {
+    var bottle = Bottle.init(std.testing.allocator);
+    defer bottle.deinit();
+
+    try std.testing.expect(0 == bottle.get_length());
+    try std.testing.expect(null == bottle._getItem("foo"));
+
+    try bottle._setItem("foo", "bar");
+    try std.testing.expect(std.mem.eql(u8, "bar", bottle._getItem("foo").?));
+
+    try bottle._removeItem("foo");
+
+    try std.testing.expect(0 == bottle.get_length());
+    try std.testing.expect(null == bottle._getItem("foo"));
+}