wyag

commit 813a8b355a68f691969c4ed9375368f0049e4f6d
parent 6f15e001fedd8c88ab6125ccb5544f182ba7ef9e
Author: Martin Ashby <martin@ashbysoft.com>
Date:   Sat, 24 Aug 2024 22:29:21 +0100

Implement basic checkout

Diffstat:
M
src/root.zig
 | 
76
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--

1 file changed, 74 insertions(+), 2 deletions(-)
diff --git a/src/root.zig b/src/root.zig
@@ -43,6 +43,13 @@ pub fn doMain() !void {
     var ls_tree_ish: argparse.Positional = .{ .name = "tree-ish", .description = "The tree-ish to log the tree for" };
     try ls_tree.addPositional(&ls_tree_ish);
 
+    var checkout: argparse.Subcommand = .{ .parent = &ap, .description = "Checkout a commit inside of a directory", .name = "checkout" };
+    try ap.addSubcommand(&checkout);
+    var checkout_commit: argparse.Positional = .{ .name = "commit", .description = "The commit to checkout" };
+    try checkout.addPositional(&checkout_commit);
+    var checkout_directory: argparse.Positional = .{ .name = "directory", .description = "The directory to checkout into" };
+    try checkout.addPositional(&checkout_directory);
+
     if (!try ap.parseOrHelp()) {
         return;
     }
@@ -85,6 +92,16 @@ pub fn doMain() !void {
         } else {
             std.log.err("No commit supplied to ls-tree", .{});
         }
+    } else if (checkout.wasExecuted) {
+        if (checkout_commit.value) |commit_ref| {
+            if (checkout_directory.value) |directory| {
+                try doCheckout(a, std.fs.cwd(), commit_ref, directory);
+            } else {
+                std.log.err("No directory was supplied to checkout", .{});
+            }
+        } else {
+            std.log.err("No commit supplied to checkout", .{});
+        }
     } else {
         if (ap.excess.items.len > 0) {
             std.log.err("Unsupported sub-command {s}, have you tried implementing it yourself?", .{ap.excess.items[0]});
@@ -95,6 +112,52 @@ pub fn doMain() !void {
     }
 }
 
+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();
+    var checkoutDir = try dir.makeOpenPath(checkout_directory, .{ .iterate = true });
+    defer checkoutDir.close();
+    var go = try repo.read_object(a, commit_ref);
+    defer go.deinit();
+    if (go.kind != .commit) return error.NotACommit;
+    var it = checkoutDir.iterate();
+    if (try it.next() != null) return error.DirNotEmpty;
+
+    var commit = try Commit.parse(a, go.reader());
+    defer commit.deinit(a);
+    var go2 = try repo.read_object(a, commit.tree);
+    defer go2.deinit();
+    try doCheckoutInternal(a, &repo, &go2, checkoutDir);
+}
+
+fn doCheckoutInternal(a: std.mem.Allocator, repo: *GitRepository, go: *GitObject, dir: std.fs.Dir) !void {
+    if (go.kind != .tree) return error.NotATree;
+    var gt = try GitTree.parse(a, go.reader());
+    defer gt.deinit();
+    for (gt.leaves.items) |leaf| {
+        var go2 = try repo.read_object_sha(a, leaf.sha);
+        defer go2.deinit();
+        switch (leaf.filetype) {
+            .file => {
+                var f = try dir.createFile(leaf.path, .{ .mode = leaf.mode });
+                defer f.close();
+                try pump(go2.reader(), f.writer());
+            },
+            .directory => {
+                var subdir = try dir.makeOpenPath(leaf.path, .{});
+                defer subdir.close();
+                try doCheckoutInternal(a, repo, &go2, subdir);
+            },
+            .symlink => {
+                return error.Unimplemented;
+            },
+            .submodule => {
+                return error.Unimplemented;
+            },
+        }
+    }
+}
+
 fn lsTree(a: std.mem.Allocator, dir: Dir, ref: []const u8, writer: anytype, recurse: bool) !void {
     var repo = try repo_find(a, dir);
     defer repo.deinit();
@@ -618,7 +681,7 @@ pub const GitTree = struct {
             }
         };
         filetype: FileType,
-        mode: u16,
+        mode: u32,
         path: []const u8,
         sha: [20]u8,
     };
@@ -643,7 +706,7 @@ pub const GitTree = struct {
             _ = try reader.readAll(&sha);
             try result.leaves.append(a, .{
                 .filetype = filetype,
-                .mode = try std.fmt.parseInt(u16, mode_str[2..], 8),
+                .mode = try std.fmt.parseInt(u32, mode_str[2..], 8),
                 .path = path,
                 .sha = sha,
             });
@@ -662,3 +725,12 @@ test "parse tree" {
     var tree = try GitTree.parse(a, fbs.reader());
     defer tree.deinit();
 }
+
+fn pump(reader: anytype, writer: anytype) !void {
+    var buf = [_]u8{0} ** std.mem.page_size;
+    while (true) {
+        const sz = try reader.read(&buf);
+        if (sz == 0) break;
+        try writer.writeAll(buf[0..sz]);
+    }
+}