From f263a8fa7121a9632c61cba8251b6272751fcbbd Mon Sep 17 00:00:00 2001
From: Matheus Catarino <matheus-catarino@hotmail.com>
Date: Wed, 1 Jan 2025 09:55:20 -0300
Subject: [PATCH] zig-build: xpack fetch - optional hash

---
 .github/workflows/build.yml |  2 +-
 build.zig                   | 66 ++++++++++++++++++++++++++++++++++++-
 build.zig.zon               |  4 ---
 3 files changed, 66 insertions(+), 6 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index ca441e7..10be922 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -93,7 +93,7 @@ jobs:
             sudo apt-get install libglu1-mesa-dev mesa-common-dev xorg-dev libasound-dev
 
       - name: (Zig) Build Shaders
-        run: zig build shaders
+        run: zig build -Dshaders
 
       - name: (Zig) Running Test
         if: runner.os != 'Windows'
diff --git a/build.zig b/build.zig
index 917f91b..3f445a2 100644
--- a/build.zig
+++ b/build.zig
@@ -1125,6 +1125,18 @@ pub fn emLinkStep(b: *Build, options: EmLinkOptions) !*Build.Step.InstallDir {
             emcc.addArg(arg);
         }
 
+        if (options.use_drt) {
+            const libdruntime = fetch(b, .{
+                .url = "https://github.com/opendlang/opend/releases/download/CI/opend-latest-xpack-emscripten.tar.xz",
+                .file_name = "lib/libdruntime-ldc.a",
+            });
+            const libphobos2 = fetch(b, .{
+                .url = "https://github.com/opendlang/opend/releases/download/CI/opend-latest-xpack-emscripten.tar.xz",
+                .file_name = "lib/libphobos2-ldc.a",
+            });
+            emcc.addFileArg(libdruntime);
+            emcc.addFileArg(libphobos2);
+        }
         // add the main lib, and then scan for library dependencies and add those too
         emcc.addArtifactArg(options.lib_main);
         for (options.lib_main.getCompileDependencies(false)) |item| {
@@ -1141,7 +1153,6 @@ pub fn emLinkStep(b: *Build, options: EmLinkOptions) !*Build.Step.InstallDir {
             .install_subdir = "web",
         });
         install.step.dependOn(&emcc.step);
-
         // get the emcc step to run on 'zig build'
         b.getInstallStep().dependOn(&install.step);
         return install;
@@ -1152,6 +1163,59 @@ pub fn emLinkStep(b: *Build, options: EmLinkOptions) !*Build.Step.InstallDir {
     });
 }
 
+// Use 'zig fetch' to download and unpack the specified URL, optionally verifying the checksum.
+fn fetch(b: *std.Build, options: struct {
+    url: []const u8,
+    file_name: []const u8,
+    hash: ?[]const u8 = null,
+}) std.Build.LazyPath {
+    const copy_from_cache = b.addRunArtifact(b.addExecutable(.{
+        .name = "copy-from-cache",
+        .root_source_file = b.addWriteFiles().add("main.zig",
+            \\const std = @import("std");
+            \\const assert = std.debug.assert;
+            \\pub fn main() !void {
+            \\    var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
+            \\    const allocator = arena.allocator();
+            \\    const args = try std.process.argsAlloc(allocator);
+            \\    assert(args.len == 5 or args.len == 6);
+            \\
+            \\    const hash_and_newline = try std.fs.cwd().readFileAlloc(allocator, args[2], 128);
+            \\    assert(hash_and_newline[hash_and_newline.len - 1] == '\n');
+            \\    const hash = hash_and_newline[0..hash_and_newline.len - 1];
+            \\    if (args.len == 6 and !std.mem.eql(u8, args[5], hash)) {
+            \\        std.debug.panic(
+            \\            \\bad hash
+            \\            \\specified:  {s}
+            \\            \\downloaded: {s}
+            \\            \\
+            \\        , .{args[5], hash, });
+            \\    }
+            \\    const source_path = try std.fs.path.join(allocator, &.{args[1], hash, args[3]});
+            \\    try std.fs.cwd().copyFile(
+            \\        source_path,
+            \\        std.fs.cwd(),
+            \\        args[4],
+            \\        .{},
+            \\    );
+            \\}
+        ),
+        .target = b.graph.host,
+    }));
+    copy_from_cache.addArg(
+        b.graph.global_cache_root.join(b.allocator, &.{"p"}) catch @panic("OOM"),
+    );
+    copy_from_cache.addFileArg(
+        b.addSystemCommand(&.{ b.graph.zig_exe, "fetch", options.url }).captureStdOut(),
+    );
+    copy_from_cache.addArg(options.file_name);
+    const result = copy_from_cache.addOutputFileArg(options.file_name);
+    if (options.hash) |hash| {
+        copy_from_cache.addArg(hash);
+    }
+    return result;
+}
+
 // build a run step which uses the emsdk emrun command to run a build target in the browser
 // NOTE: ideally this would go into a separate emsdk-zig package
 pub const EmRunOptions = struct {
diff --git a/build.zig.zon b/build.zig.zon
index 6f1eeb3..1b14b1d 100644
--- a/build.zig.zon
+++ b/build.zig.zon
@@ -26,9 +26,5 @@
             .hash = "122007ff9e979a63058e3af1de1d8b98957baa741a8b779d50f9b251dca4acf60b41",
             .lazy = true,
         },
-        .xpack = .{
-            .url = "https://github.com/opendlang/opend/releases/download/CI/opend-latest-xpack-emscripten.tar.xz",
-            .hash = "1220132c994d2f9754174c5fe934413f3fc79603d1a180429bb231aaed6110429cc6",
-        },
     },
 }