WIP: CDP

Signed-off-by: Francis Bouvier <francis@lightpanda.io>

src/cdp/cdp.zig

@@ -0,0 +1,87 @@
+const std = @import("std");
+
+const server = @import("../server.zig");
+const Ctx = server.CmdContext;
+const SendFn = server.SendFn;
+const browser = @import("browser.zig").browser;
+const target = @import("target.zig").target;
+
+const Domains = enum {
+    Browser,
+    Target,
+};
+
+// The caller is responsible for calling `free` on the returned slice.
+pub fn do(
+    alloc: std.mem.Allocator,
+    s: []const u8,
+    ctx: *Ctx,
+    comptime sendFn: SendFn,
+) ![]const u8 {
+    var scanner = std.json.Scanner.initCompleteInput(alloc, s);
+    defer scanner.deinit();
+
+    std.debug.assert(try scanner.next() == .object_begin);
+
+    try checkKey("id", (try scanner.next()).string);
+    const id = try std.fmt.parseUnsigned(u64, (try scanner.next()).number, 10);
+
+    try checkKey("method", (try scanner.next()).string);
+    const method = (try scanner.next()).string;
+
+    std.log.debug("cmd: id {any}, method {s}\n", .{ id, method });
+
+    var iter = std.mem.splitScalar(u8, method, '.');
+    const domain = std.meta.stringToEnum(Domains, iter.first()) orelse
+        return error.UnknonwDomain;
+
+    return switch (domain) {
+        .Browser => browser(alloc, id, iter.next().?, &scanner, ctx, sendFn),
+        .Target => target(alloc, id, iter.next().?, &scanner, ctx, sendFn),
+    };
+}
+
+// Utils
+// -----
+
+fn checkKey(key: []const u8, token: []const u8) !void {
+    if (!std.mem.eql(u8, key, token)) return error.WrongToken;
+}
+
+const resultNull = "{{\"id\": {d}, \"result\": {{}}}}";
+
+pub fn result(
+    alloc: std.mem.Allocator,
+    id: u64,
+    comptime T: ?type,
+    res: anytype,
+) ![]const u8 {
+    if (T == null) return try std.fmt.allocPrint(alloc, resultNull, .{id});
+
+    const Resp = struct {
+        id: u64,
+        result: T.?,
+    };
+    const resp = Resp{ .id = id, .result = res };
+
+    var out = std.ArrayList(u8).init(alloc);
+    defer out.deinit();
+
+    try std.json.stringify(resp, .{}, out.writer());
+    const ret = try alloc.alloc(u8, out.items.len);
+    @memcpy(ret, out.items);
+    return ret;
+}
+
+pub fn getParams(
+    alloc: std.mem.Allocator,
+    comptime T: type,
+    scanner: *std.json.Scanner,
+) !T {
+    try checkKey("params", (try scanner.next()).string);
+    const options = std.json.ParseOptions{
+        .max_value_len = scanner.input.len,
+        .allocate = .alloc_if_needed,
+    };
+    return std.json.innerParse(T, alloc, scanner, options);
+}