wyag

commit 040307b324692a6146ddcb903f190879547dea7a
parent 813a8b355a68f691969c4ed9375368f0049e4f6d
Author: Martin Ashby <martin@ashbysoft.com>
Date:   Mon, 26 Aug 2024 22:02:29 +0100

Implement show-ref

Diffstat:
M
src/root.zig
 | 
73
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 73 insertions(+), 0 deletions(-)
diff --git a/src/root.zig b/src/root.zig
@@ -50,6 +50,9 @@ pub fn doMain() !void {
     var checkout_directory: argparse.Positional = .{ .name = "directory", .description = "The directory to checkout into" };
     try checkout.addPositional(&checkout_directory);
 
+    var show_ref: argparse.Subcommand = .{ .parent = &ap, .description = "List references in a local repository", .name = "show-ref" };
+    try ap.addSubcommand(&show_ref);
+
     if (!try ap.parseOrHelp()) {
         return;
     }
@@ -102,6 +105,8 @@ pub fn doMain() !void {
         } else {
             std.log.err("No commit supplied to checkout", .{});
         }
+    } else if (show_ref.wasExecuted) {
+        try doShowRef(a, std.fs.cwd(), std.io.getStdOut().writer());
     } else {
         if (ap.excess.items.len > 0) {
             std.log.err("Unsupported sub-command {s}, have you tried implementing it yourself?", .{ap.excess.items[0]});
@@ -112,6 +117,23 @@ pub fn doMain() !void {
     }
 }
 
+fn doShowRef(a: std.mem.Allocator, dir: std.fs.Dir, writer: anytype) !void {
+    var repo = try repo_find(a, dir);
+    defer repo.deinit();
+    var refs = try repo.ref_list(a);
+    defer {
+        var it = refs.iterator();
+        while (it.next()) |e| {
+            a.free(e.key_ptr.*);
+        }
+        refs.deinit();
+    }
+    var it = refs.iterator();
+    while (it.next()) |e| {
+        try std.fmt.format(writer, "{} refs/{s}\n", .{ std.fmt.fmtSliceHexLower(&(e.value_ptr.*)), e.key_ptr.* });
+    }
+}
+
 fn doCheckout(a: std.mem.Allocator, dir: std.fs.Dir, commit_ref: []const u8, checkout_directory: []const u8) !void {
     var repo = try repo_find(a, dir);
     defer repo.deinit();
@@ -453,6 +475,57 @@ pub const GitRepository = struct {
         }
         return try ca.dupe(u8, ref);
     }
+
+    pub fn resolve(self: GitRepository, a: std.mem.Allocator, ref: []const u8) ![20]u8 {
+        const ref_file_path = try std.fs.path.join(a, &.{ "refs", ref });
+        defer a.free(ref_file_path);
+        const ref_file_content = try self.gitdir.readFileAlloc(a, ref_file_path, 1024);
+        defer a.free(ref_file_content);
+        if (std.mem.startsWith(u8, ref_file_content, "ref: ")) {
+            return try resolve(self, a, ref_file_content[5..]);
+        } else {
+            var res: [20]u8 = undefined;
+            _ = try std.fmt.hexToBytes(&res, std.mem.trim(u8, ref_file_content, &std.ascii.whitespace));
+            return res;
+        }
+    }
+
+    // Caller owns the map and the keys to the map.
+    pub fn ref_list(self: GitRepository, a: std.mem.Allocator) !std.StringArrayHashMap([20]u8) {
+        var res = std.StringArrayHashMap([20]u8).init(a);
+        errdefer {
+            var it = res.iterator();
+            while (it.next()) |e| {
+                a.free(e.key_ptr.*);
+            }
+            res.deinit();
+        }
+
+        const ref_dir = try self.gitdir.openDir("refs", .{ .iterate = true });
+        var walker = try ref_dir.walk(a);
+        defer walker.deinit();
+        while (try walker.next()) |we| {
+            if (we.kind == .file) {
+                const ref = try self.resolve(a, we.path);
+                const key = try a.dupe(u8, we.path);
+                errdefer a.free(key);
+                try res.put(key, ref);
+            }
+        }
+        //`fn lessThan(ctx: @TypeOf(ctx), a_index: usize, b_index: usize) bool`
+        const Srt = struct {
+            map: std.StringArrayHashMap([20]u8),
+            pub fn lessThan(slf: *@This(), ai: usize, bi: usize) bool {
+                const keys = slf.map.keys();
+                const ka = keys[ai];
+                const kb = keys[bi];
+                return std.mem.lessThan(u8, ka, kb);
+            }
+        };
+        var srt = Srt{ .map = res };
+        res.sort(&srt);
+        return res;
+    }
 };
 
 test "init repo" {