Implement sending command from riverctl

These commands are successfully received by the server, but not yet
executed.

build.zig

@@ -19,39 +19,53 @@ pub fn build(b: *std.build.Builder) !void {
 
     const scan_protocols = ScanProtocolsStep.create(b);
 
-    const river = b.addExecutable("river", "src/river.zig");
-    river.setTarget(target);
-    river.setBuildMode(mode);
-    river.addBuildOption(bool, "xwayland", xwayland);
-    addServerDeps(river, &scan_protocols.step);
-    river.install();
+    {
+        const river = b.addExecutable("river", "src/river.zig");
+        river.setTarget(target);
+        river.setBuildMode(mode);
+        river.addBuildOption(bool, "xwayland", xwayland);
 
-    const run_cmd = river.run();
-    run_cmd.step.dependOn(b.getInstallStep());
+        addProtocolDeps(river, &scan_protocols.step);
+        addServerDeps(river);
 
-    const run_step = b.step("run", "Run the compositor");
-    run_step.dependOn(&run_cmd.step);
+        river.install();
 
-    const riverctl = b.addExecutable("riverctl", "src/riverctl.zig");
-    riverctl.setTarget(target);
-    riverctl.setBuildMode(mode);
-    riverctl.install();
+        const run_cmd = river.run();
+        run_cmd.step.dependOn(b.getInstallStep());
 
-    const river_test = b.addTest("src/test_main.zig");
-    river_test.setTarget(target);
-    river_test.setBuildMode(mode);
-    river_test.addBuildOption(bool, "xwayland", xwayland);
-    addServerDeps(river_test, &scan_protocols.step);
+        const run_step = b.step("run", "Run the compositor");
+        run_step.dependOn(&run_cmd.step);
+    }
 
-    const test_step = b.step("test", "Run the tests");
-    test_step.dependOn(&river_test.step);
+    {
+        const riverctl = b.addExecutable("riverctl", "src/riverctl.zig");
+        riverctl.setTarget(target);
+        riverctl.setBuildMode(mode);
+
+        addProtocolDeps(riverctl, &scan_protocols.step);
+
+        riverctl.linkLibC();
+
+        riverctl.linkSystemLibrary("wayland-client");
+
+        riverctl.install();
+    }
+
+    {
+        const river_test = b.addTest("src/test_main.zig");
+        river_test.setTarget(target);
+        river_test.setBuildMode(mode);
+        river_test.addBuildOption(bool, "xwayland", xwayland);
+
+        addProtocolDeps(river_test, &scan_protocols.step);
+        addServerDeps(river_test);
+
+        const test_step = b.step("test", "Run the tests");
+        test_step.dependOn(&river_test.step);
+    }
 }
 
-fn addServerDeps(exe: *std.build.LibExeObjStep, protocol_step: *std.build.Step) void {
-    exe.step.dependOn(protocol_step);
-    exe.addIncludeDir("protocol");
-    exe.addCSourceFile("protocol/river-window-management-unstable-v1-protocol.c", &[_][]const u8{"-std=c99"});
-
+fn addServerDeps(exe: *std.build.LibExeObjStep) void {
     exe.addCSourceFile("include/bindings.c", &[_][]const u8{"-std=c99"});
     exe.addIncludeDir(".");
 
@@ -62,6 +76,12 @@ fn addServerDeps(exe: *std.build.LibExeObjStep, protocol_step: *std.build.Step)
     exe.linkSystemLibrary("xkbcommon");
 }
 
+fn addProtocolDeps(exe: *std.build.LibExeObjStep, protocol_step: *std.build.Step) void {
+    exe.step.dependOn(protocol_step);
+    exe.addIncludeDir("protocol");
+    exe.addCSourceFile("protocol/river-window-management-unstable-v1-protocol.c", &[_][]const u8{"-std=c99"});
+}
+
 const ScanProtocolsStep = struct {
     builder: *std.build.Builder,
     step: std.build.Step,
@@ -116,6 +136,18 @@ const ScanProtocolsStep = struct {
             _ = try self.builder.exec(
                 &[_][]const u8{ "wayland-scanner", "private-code", xml_in_path, code_out_path },
             );
+
+            // We need the client header as well for river-window-management
+            if (std.mem.eql(u8, basename_no_ext, "river-window-management-unstable-v1")) {
+                const client_header_out_path = try std.mem.concat(
+                    self.builder.allocator,
+                    u8,
+                    &[_][]const u8{ "protocol/", basename_no_ext, "-client-protocol.h" },
+                );
+                _ = try self.builder.exec(
+                    &[_][]const u8{ "wayland-scanner", "client-header", xml_in_path, client_header_out_path },
+                );
+            }
         }
     }
 };

protocol/river-window-management-unstable-v1.xml

@@ -27,7 +27,8 @@
         A complete list of commands will be found in the man page.
         TODO: write the man page.
       </description>
-      <arg name="command" type="string" summary="the command to run"/>
+      <arg name="command" type="array" summary="the command to run as a series
+        of null-terminated strings"/>
     </request>
 
     <enum name="error">

src/WindowManagement.zig

@@ -36,6 +36,7 @@ wl_global: *c.wl_global,
 listen_display_destroy: c.wl_listener,
 
 pub fn init(self: *Self, server: *Server) !void {
+    self.server = server;
     self.wl_global = c.wl_global_create(
         server.wl_display,
         &c.zriver_window_manager_v1_interface,
@@ -72,6 +73,22 @@ fn resourceDestroy(wl_resource: ?*c.wl_resource) callconv(.C) void {
     // TODO
 }
 
-fn runCommand(wl_client: ?*c.wl_client, wl_resource: ?*c.wl_resource, command: ?[*:0]const u8) callconv(.C) void {
-    Log.Debug.log("command: {}", .{command});
+fn runCommand(wl_client: ?*c.wl_client, wl_resource: ?*c.wl_resource, command: ?*c.wl_array) callconv(.C) void {
+    const self = @ptrCast(*Self, @alignCast(@alignOf(*Self), c.wl_resource_get_user_data(wl_resource)));
+    const allocator = self.server.allocator;
+
+    var args = std.ArrayList([]const u8).init(allocator);
+
+    var i: usize = 0;
+    const data = @ptrCast([*]const u8, command.?.data);
+    while (i < command.?.size) {
+        const slice = std.mem.spanZ(@ptrCast([*:0]const u8, &data[i]));
+        args.append(std.mem.dupe(allocator, u8, slice) catch unreachable) catch unreachable;
+
+        i += slice.len + 1;
+    }
+
+    for (args.items) |x| {
+        std.debug.warn("{}\n", .{x});
+    }
 }

src/riverctl.zig

@@ -18,9 +18,62 @@
 const std = @import("std");
 
 const c = @cImport({
-    @cInclude();
+    @cInclude("wayland-client.h");
+    @cInclude("river-window-management-unstable-v1-client-protocol.h");
 });
 
-pub fn main() void {
-    std.debug.warn("hello world\n", .{});
+const wl_registry_listener = c.wl_registry_listener{
+    .global = handleGlobal,
+    .global_remove = handleGlobalRemove,
+};
+
+var river_window_manager: ?*c.zriver_window_manager_v1 = null;
+
+pub fn main() !void {
+    const wl_display = c.wl_display_connect(null) orelse return error.CantConnectToDisplay;
+    const wl_registry = c.wl_display_get_registry(wl_display);
+
+    _ = c.wl_registry_add_listener(wl_registry, &wl_registry_listener, null);
+    if (c.wl_display_roundtrip(wl_display) == -1) return error.RoundtripFailed;
+
+    const wm = river_window_manager orelse return error.RiverWMNotAdvertised;
+
+    var command: c.wl_array = undefined;
+    c.wl_array_init(&command);
+    var it = std.process.args();
+    // Skip our name
+    _ = it.nextPosix();
+    while (it.nextPosix()) |arg| {
+        // Add one as we need to copy the null terminators as well
+        var ptr = @ptrCast([*]u8, c.wl_array_add(&command, arg.len + 1) orelse
+            return error.OutOfMemory);
+        for (arg) |ch, i| ptr[i] = ch;
+        ptr[arg.len] = 0;
+    }
+
+    c.zriver_window_manager_v1_run_command(wm, &command);
+    if (c.wl_display_roundtrip(wl_display) == -1) return error.RoundtripFailed;
 }
+
+fn handleGlobal(
+    data: ?*c_void,
+    wl_registry: ?*c.wl_registry,
+    name: u32,
+    interface: ?[*:0]const u8,
+    version: u32,
+) callconv(.C) void {
+    // We only care about the river_window_manager global
+    if (std.mem.eql(
+        u8,
+        std.mem.spanZ(interface.?),
+        std.mem.spanZ(@ptrCast([*:0]const u8, c.zriver_window_manager_v1_interface.name.?)),
+    )) {
+        river_window_manager = @ptrCast(
+            *c.zriver_window_manager_v1,
+            c.wl_registry_bind(wl_registry, name, &c.zriver_window_manager_v1_interface, 1),
+        );
+    }
+}
+
+/// Ignore the event
+fn handleGlobalRemove(data: ?*c_void, wl_registry: ?*c.wl_registry, name: u32) callconv(.C) void {}