Files
vulkan-zig/generator/vulkan/build-integration.zig
2020-08-10 01:22:32 +02:00

68 lines
3.1 KiB
Zig

const std = @import("std");
const generate = @import("generator.zig").generate;
const path = std.fs.path;
const Builder = std.build.Builder;
const Step = std.build.Step;
/// build.zig integration for Vulkan binding generation. This step can be used to generate
/// Vulkan bindings at compiletime from vk.xml, by providing the path to vk.xml and the output
/// path relative to zig-cache. The final package can then be obtained by `package()`, the result
/// of which can be added to the project using `std.build.Builder.addPackage`.
pub const GenerateStep = struct {
step: Step,
builder: *Builder,
/// The path to vk.xml
spec_path: []const u8,
/// The package representing the generated bindings. The generated bindings will be placed
/// in `package.path`. When using this step, this member should be passed to
/// `std.build.Builder.addPackage`, which causes the bindings to become available under the
/// name `vulkan`.
package: std.build.Pkg,
/// Initialize a Vulkan generation step, for `builder`. `spec_path` is the path to
/// vk.xml, relative to the project root. The generated bindings will be placed at
/// `out_path`, which is relative to the zig-cache directory.
pub fn init(builder: *Builder, spec_path: []const u8, out_path: []const u8) *GenerateStep {
const self = builder.allocator.create(GenerateStep) catch unreachable;
const full_out_path = path.join(builder.allocator, &[_][]const u8{
builder.build_root,
builder.cache_root,
out_path,
}) catch unreachable;
self.* = .{
.step = Step.init(.Custom, "vulkan-generate", builder.allocator, make),
.builder = builder,
.spec_path = spec_path,
.package = .{
.name = "vulkan",
.path = full_out_path,
.dependencies = null,
}
};
return self;
}
/// Internal build function. This reads `vk.xml`, and passes it to `generate`, which then generates
/// the final bindings. The resulting generated bindings are not formatted, which is why an ArrayList
/// writer is passed instead of a file writer. This is then formatted into standard formatting
/// by parsing it and rendering with `std.zig.parse` and `std.zig.render` respectively.
fn make(step: *Step) !void {
const self = @fieldParentPtr(GenerateStep, "step", step);
const cwd = std.fs.cwd();
var out_buffer = std.ArrayList(u8).init(self.builder.allocator);
const spec = try cwd.readFileAlloc(self.builder.allocator, self.spec_path, std.math.maxInt(usize));
try generate(self.builder.allocator, spec, out_buffer.writer());
const tree = try std.zig.parse(self.builder.allocator, out_buffer.items);
const dir = path.dirname(self.package.path).?;
try cwd.makePath(dir);
const output_file = cwd.createFile(self.package.path, .{}) catch unreachable;
defer output_file.close();
_ = try std.zig.render(self.builder.allocator, output_file.outStream(), tree);
}
};