build: switch to the Zig package manager

No more git submodules!

PACKAGING.md

@@ -26,6 +26,45 @@ and is only compatible with that release and any patch releases. At the time
 of writing for example river is compatible with Zig 0.9.0 and 0.9.1 but
 not Zig 0.8.0 or 0.10.0.
 
+## Zig Package Manager
+
+River uses the built-in Zig package manager for its (few) Zig dependencies.
+By default, running `zig build` will fetch river's Zig dependencies from the
+internet and store them in the global zig cache before building river. Since
+accessing the internet is forbidden or at least frowned upon by most distro
+packaging infrastructure, there are ways to fetch the Zig dependencies in a
+separate step before building river:
+
+1. Fetch step with internet access:
+
+   For each package in the `build.zig.zon` manifest file run the following command
+   with the tarball URL in the `build.zig.zon`:
+
+   ```
+   zig fetch --global-cache-dir /tmp/foobar $URL
+   ```
+
+   This command will download and unpack the tarball, hash the contents of the
+   tarball, and store the contents in the `/tmp/foobar/p/$HASH` directory. This
+   hash should match the corresponding hash field in the `build.zig.zon`.
+
+2. Build step with no internet access:
+
+   The `--system` flag for `zig build` takes a path to an arbitrary directory in
+   which zig packages stored in subdirectories matching their hash can be found.
+
+   ```
+   zig build --system /tmp/foobar/p/ ...
+   ```
+
+   This flag will disable all internet access and error if a package is not found
+   in the provided directory.
+
+It is also possible for distros to distribute Zig package manager packages as
+distro packages, although there are still some rough edges as the support for
+this is not yet mature. See this patchset for Chimera Linux for an example of
+how this can work: https://github.com/chimera-linux/cports/pull/1395
+
 ## Build options
 
 River is built using the Zig build system. To see all available build

README.md

@@ -51,12 +51,7 @@ commands to set up the user's configuration.
 
 ## Building
 
-On cloning the repository, you must init and update the submodules as well
-with e.g.
-
-```
-git submodule update --init
-```
+Note: If you are packaging river for distribution, see [PACKAGING.md](PACKAGING.md).
 
 To compile river first ensure that you have the following dependencies
 installed. The "development" versions are required if applicable to your
@@ -76,10 +71,7 @@ Then run, for example:
 ```
 zig build -Doptimize=ReleaseSafe --prefix ~/.local install
 ```
-To enable experimental Xwayland support pass the `-Dxwayland` option as well.
-
-If you are packaging river for distribution, see also
-[PACKAGING.md](PACKAGING.md).
+To enable Xwayland support pass the `-Dxwayland` option as well.
 
 ## Usage
 

build.zig

@@ -4,7 +4,7 @@ const Build = std.Build;
 const fs = std.fs;
 const mem = std.mem;
 
-const Scanner = @import("deps/zig-wayland/build.zig").Scanner;
+const Scanner = @import("zig-wayland").Scanner;
 
 /// While a river release is in development, this string should contain the version in development
 /// with the "-dev" suffix.
@@ -132,32 +132,20 @@ pub fn build(b: *Build) !void {
     scanner.generate("zwlr_layer_shell_v1", 4);
     scanner.generate("zwlr_output_power_manager_v1", 1);
 
-    const wayland = b.createModule(.{
-        .root_source_file = scanner.result,
-        .target = target,
-    });
-
-    const xkbcommon = b.createModule(.{
-        .root_source_file = .{ .path = "deps/zig-xkbcommon/src/xkbcommon.zig" },
-        .target = target,
-    });
-    xkbcommon.linkSystemLibrary("xkbcommon", .{});
-
-    const pixman = b.createModule(.{
-        .root_source_file = .{ .path = "deps/zig-pixman/pixman.zig" },
-        .target = target,
-    });
-    pixman.linkSystemLibrary("pixman-1", .{});
-
-    const wlroots = b.createModule(.{
-        .root_source_file = .{ .path = "deps/zig-wlroots/src/wlroots.zig" },
-        .imports = &.{
-            .{ .name = "wayland", .module = wayland },
-            .{ .name = "xkbcommon", .module = xkbcommon },
-            .{ .name = "pixman", .module = pixman },
-        },
-        .target = target,
-    });
+    const wayland = b.createModule(.{ .root_source_file = scanner.result });
+
+    const xkbcommon = b.dependency("zig-xkbcommon", .{}).module("xkbcommon");
+    const pixman = b.dependency("zig-pixman", .{}).module("pixman");
+
+    const wlroots = b.dependency("zig-wlroots", .{}).module("wlroots");
+    wlroots.addImport("wayland", wayland);
+    wlroots.addImport("xkbcommon", xkbcommon);
+    wlroots.addImport("pixman", pixman);
+
+    // We need to ensure the wlroots include path obtained from pkg-config is
+    // exposed to the wlroots module for @cImport() to work. This seems to be
+    // the best way to do so with the current std.Build API.
+    wlroots.resolved_target = target;
     wlroots.linkSystemLibrary("wlroots", .{});
 
     const flags = b.createModule(.{ .root_source_file = .{ .path = "common/flags.zig" } });
@@ -179,6 +167,9 @@ pub fn build(b: *Build) !void {
         river.linkSystemLibrary("libevdev");
         river.linkSystemLibrary("libinput");
         river.linkSystemLibrary("wayland-server");
+        river.linkSystemLibrary("wlroots");
+        river.linkSystemLibrary("xkbcommon");
+        river.linkSystemLibrary("pixman-1");
 
         river.root_module.addImport("wayland", wayland);
         river.root_module.addImport("xkbcommon", xkbcommon);
@@ -191,7 +182,6 @@ pub fn build(b: *Build) !void {
             .file = .{ .path = "river/wlroots_log_wrapper.c" },
             .flags = &.{ "-std=c99", "-O2" },
         });
-        river.linkSystemLibrary("wlroots");
 
         // TODO: remove when zig issue #131 is implemented
         scanner.addCSource(river);

build.zig.zon

@@ -0,0 +1,23 @@
+.{
+    .name = "river",
+    .version = "0.4.0-dev",
+    .paths = .{""},
+    .dependencies = .{
+        .@"zig-pixman" = .{
+            .url = "https://codeberg.org/ifreund/zig-pixman/archive/v0.1.0.tar.gz",
+            .hash = "122014eeb4600a059bdcfe1c864862f17e6d5e4237e3bb7d6818f2a5583f6f4eb843",
+        },
+        .@"zig-wayland" = .{
+            .url = "https://codeberg.org/ifreund/zig-wayland/archive/v0.1.0.tar.gz",
+            .hash = "1220b0f8f822c1625af7aae4cb3ab2c4ec1a4c0e99ef32867b2a8d88bb070b3e7f6d",
+        },
+        .@"zig-wlroots" = .{
+            .url = "https://codeberg.org/ifreund/zig-wlroots/archive/v0.17.0.tar.gz",
+            .hash = "1220714d1cc39c3abb1d9c22a0b838d847ead099cb7d9931821490483f30c022e827",
+        },
+        .@"zig-xkbcommon" = .{
+            .url = "https://codeberg.org/ifreund/zig-xkbcommon/archive/v0.1.0.tar.gz",
+            .hash = "1220840390382c88caf9b0887f6cebbba3a7d05960b8b2ee6d80567b2950b71e5017",
+        },
+    },
+}