refactor: switch git blame to incremental output mode

Also, move blame parser and related structures to a new module VcsBlame.

This includes a full parser re-write to take advantage of the slightly
more efficient incremental output format.

build.zig

@@ -418,6 +418,11 @@ pub fn build_exe(
         .imports = &.{},
     });
 
+    const VcsBlame_mod = b.createModule(.{
+        .root_source_file = b.path("src/VcsBlame.zig"),
+        .imports = &.{},
+    });
+
     const color_mod = b.createModule(.{
         .root_source_file = b.path("src/color.zig"),
     });
@@ -449,6 +454,7 @@ pub fn build_exe(
             .{ .name = "TypedInt", .module = TypedInt_mod },
             .{ .name = "vaxis", .module = vaxis_mod },
             .{ .name = "file_type_config", .module = file_type_config_mod },
+            .{ .name = "VcsBlame", .module = VcsBlame_mod },
         },
     });
 

src/VcsBlame.zig

@@ -0,0 +1,146 @@
+commits: std.ArrayList(Commit) = .empty,
+lines: std.ArrayList(?u16) = .empty,
+content: std.ArrayList(u8) = .empty,
+
+pub const Commit = struct {
+    // {sha1} {src_line_no} {dst_line_no} {line_count}
+    id: []const u8 = &.{},
+
+    // author {text}
+    author: []const u8 = &.{},
+
+    // author-mail {email}
+    @"author-mail": []const u8 = &.{},
+
+    // author-time {timestamp}
+    @"author-time": i64 = 0,
+
+    // author-tz {TZ}
+    @"author-tz": i16 = 0,
+
+    // committer {text}
+    // committer-mail {email}
+    // committer-time {timestamp}
+    // committer-tz {TZ}
+
+    // summary {text}
+    summary: []const u8 = &.{},
+
+    // previous {sha1} {filename}
+    // filename {filename}
+};
+
+pub fn getLine(self: *const @This(), line: usize) ?*const Commit {
+    if (line >= self.lines.items.len) return null;
+    const commit_no = self.lines.items[line] orelse return null;
+    return &self.commits.items[commit_no];
+}
+
+pub fn addContent(self: *@This(), allocator: std.mem.Allocator, content: []const u8) error{OutOfMemory}!void {
+    return self.content.appendSlice(allocator, content);
+}
+
+pub const Error = error{
+    OutOfMemory,
+    InvalidBlameCommitHash,
+    InvalidBlameCommitSrcLine,
+    InvalidBlameCommitLine,
+    InvalidBlameCommitLines,
+    InvalidBlameHeaderName,
+    InvalidBlameHeaderValue,
+    InvalidBlameLineNo,
+    InvalidBlameLines,
+    InvalidAuthorTime,
+    InvalidAuthorTz,
+};
+
+pub fn parse(self: *@This(), allocator: std.mem.Allocator) Error!void {
+    self.commits.deinit(allocator);
+    self.lines.deinit(allocator);
+    self.commits = .empty;
+    self.lines = .empty;
+
+    var existing: std.StringHashMapUnmanaged(usize) = .empty;
+    defer existing.deinit(allocator);
+
+    const headers = enum { author, @"author-mail", @"author-time", @"author-tz", summary, filename };
+
+    var state: enum { root, commit, headers } = .root;
+    var commit: Commit = .{};
+    var line_no: usize = 0;
+    var lines: usize = 1;
+
+    var it = std.mem.splitScalar(u8, self.content.items, '\n');
+    while (it.next()) |line| {
+        top: switch (state) {
+            .root => {
+                commit = .{};
+                line_no = 0;
+                lines = 0;
+                state = .commit;
+                continue :top .commit;
+            },
+            .commit => { // 35be98f95ca999a112ad3aff0932be766f702e13 141 141 1
+                var arg = std.mem.splitScalar(u8, line, ' ');
+                commit.id = arg.next() orelse return error.InvalidBlameCommitHash;
+                _ = arg.next() orelse return error.InvalidBlameCommitSrcLine;
+                line_no = std.fmt.parseInt(usize, arg.next() orelse return error.InvalidBlameCommitLine, 10) catch return error.InvalidBlameLineNo;
+                lines = std.fmt.parseInt(usize, arg.next() orelse return error.InvalidBlameCommitLines, 10) catch return error.InvalidBlameLines;
+                state = .headers;
+            },
+            .headers => {
+                var arg = std.mem.splitScalar(u8, line, ' ');
+                const name = arg.next() orelse return error.InvalidBlameHeaderName;
+                if (name.len == line.len) return error.InvalidBlameHeaderValue;
+                const value = line[name.len + 1 ..];
+                if (std.meta.stringToEnum(headers, name)) |header| switch (header) {
+                    .author => {
+                        commit.author = value;
+                    },
+                    .@"author-mail" => {
+                        commit.@"author-mail" = value;
+                    },
+                    .@"author-time" => {
+                        commit.@"author-time" = std.fmt.parseInt(@TypeOf(commit.@"author-time"), value, 10) catch return error.InvalidAuthorTime;
+                    },
+                    .@"author-tz" => {
+                        commit.@"author-tz" = std.fmt.parseInt(@TypeOf(commit.@"author-tz"), value, 10) catch return error.InvalidAuthorTz;
+                    },
+                    .summary => {
+                        commit.summary = value;
+                    },
+                    .filename => {
+                        line_no -|= 1;
+                        const to_line_no = line_no + lines;
+                        const commit_no: usize = if (existing.get(commit.id)) |n| n else blk: {
+                            const n = self.commits.items.len;
+                            try existing.put(allocator, commit.id, self.commits.items.len);
+                            (try self.commits.addOne(allocator)).* = commit;
+                            break :blk n;
+                        };
+                        if (self.lines.items.len < to_line_no) {
+                            try self.lines.ensureTotalCapacity(allocator, to_line_no);
+                            while (self.lines.items.len < to_line_no)
+                                (try self.lines.addOne(allocator)).* = null;
+                        }
+                        for (line_no..to_line_no) |ln|
+                            self.lines.items[ln] = @intCast(commit_no);
+
+                        state = .root;
+                    },
+                };
+            },
+        }
+    }
+}
+
+pub fn reset(self: *@This(), allocator: std.mem.Allocator) void {
+    self.commits.deinit(allocator);
+    self.lines.deinit(allocator);
+    self.content.deinit(allocator);
+    self.commits = .empty;
+    self.lines = .empty;
+    self.content = .empty;
+}
+
+const std = @import("std");

src/buffer/Buffer.zig

@@ -2,6 +2,7 @@ const std = @import("std");
 const builtin = @import("builtin");
 const cbor = @import("cbor");
 const TypedInt = @import("TypedInt");
+const VcsBlame = @import("VcsBlame");
 const file_type_config = @import("file_type_config");
 const Allocator = std.mem.Allocator;
 const ArrayList = std.ArrayList;
@@ -55,8 +56,7 @@ meta: ?[]const u8 = null,
 lsp_version: usize = 1,
 vcs_id: ?[]const u8 = null,
 vcs_content: ?ArrayList(u8) = null,
-vcs_blame: ?ArrayList(u8) = null,
-vcs_blame_items: ArrayList(BlameLine) = .empty,
+vcs_blame: VcsBlame = .{},
 last_view: ?usize = null,
 
 undo_head: ?*UndoNode = null,
@@ -1220,7 +1220,7 @@ pub fn create(allocator: Allocator) error{OutOfMemory}!*Self {
 pub fn deinit(self: *Self) void {
     self.clear_vcs_content();
     self.clear_vcs_blame();
-    self.vcs_blame_items.deinit(self.allocator);
+    self.vcs_blame.reset(self.external_allocator);
     if (self.vcs_id) |buf| self.external_allocator.free(buf);
     if (self.meta) |buf| self.external_allocator.free(buf);
     if (self.file_buf) |buf| self.external_allocator.free(buf);
@@ -1298,89 +1298,19 @@ pub fn get_vcs_content(self: *const Self) ?[]const u8 {
 }
 
 pub fn clear_vcs_blame(self: *Self) void {
-    if (self.vcs_blame) |*buf| {
-        buf.deinit(self.external_allocator);
-        self.vcs_blame = null;
-    }
+    self.vcs_blame.reset(self.external_allocator);
 }
 
-pub fn get_vcs_blame(self: *const Self) ?[]const u8 {
-    return if (self.vcs_blame) |*buf| buf.items else null;
+pub fn get_vcs_blame(self: *const Self, line: usize) ?*const VcsBlame.Commit {
+    return self.vcs_blame.getLine(line);
 }
 
 pub fn set_vcs_blame(self: *Self, vcs_blame: []const u8) error{OutOfMemory}!void {
-    if (self.vcs_blame) |*al| {
-        try al.appendSlice(self.external_allocator, vcs_blame);
-    } else {
-        var al: ArrayList(u8) = .empty;
-        try al.appendSlice(self.external_allocator, vcs_blame);
-        self.vcs_blame = al;
-    }
+    return self.vcs_blame.addContent(self.external_allocator, vcs_blame);
 }
 
-/// Can probably be optimized
-pub fn parse_git_blame(self: *Self) !void {
-    self.vcs_blame_items.clearAndFree(self.allocator);
-    var stream = std.io.fixedBufferStream(self.vcs_blame.?.items);
-    var reader = stream.reader();
-    var chunk_active = false;
-    var current_committer: []u8 = "";
-    var current_stamp: usize = undefined;
-    var buffer: [200]u8 = undefined;
-    while (true) {
-        const line = reader.readUntilDelimiter(&buffer, '\n') catch {
-            break;
-        };
-
-        if (line.len == 0)
-            continue;
-
-        if (line.len >= 40 and std.ascii.isHex(line[0])) {
-            if (chunk_active)
-                break; // error
-
-            chunk_active = true;
-            var it = std.mem.splitScalar(u8, line, ' ');
-
-            const sha = it.next() orelse continue;
-            if (sha.len != 40) continue;
-
-            _ = it.next(); // original line (ignored)
-            const number = try std.fmt.parseInt(
-                i64,
-                it.next() orelse break,
-                10,
-            );
-            if (number != self.vcs_blame_items.items.len + 1)
-                break;
-        } else if (std.mem.startsWith(u8, line, "author ")) {
-            if (!chunk_active)
-                break; // error
-            current_committer = try self.allocator.dupe(
-                u8,
-                line["author ".len..],
-            );
-        } else if (std.mem.startsWith(u8, line, "author-time ")) {
-            if (!chunk_active)
-                break; // error
-            current_stamp = try std.fmt.parseInt(
-                usize,
-                line["author-time ".len..],
-                10,
-            );
-
-            const ptr = try self.vcs_blame_items.addOne(self.allocator);
-            ptr.* = BlameLine{ .author_name = current_committer, .author_stamp = current_stamp };
-            chunk_active = false;
-        }
-    }
-}
-
-pub fn get_line_blame(self: *const Self, line: usize) ?[]const u8 {
-    if (line + 1 > self.vcs_blame_items.items.len)
-        return null;
-
-    return self.vcs_blame_items.items[line].author_name;
+pub fn parse_vcs_blame(self: *Self) VcsBlame.Error!void {
+    return self.vcs_blame.parse(self.external_allocator);
 }
 
 pub fn update_last_used_time(self: *Self) void {

src/git.zig

@@ -390,7 +390,7 @@ pub fn blame(context_: usize, file_path: []const u8) !void {
     try arg.writer.print("{s}", .{file_path});
     try git(context_, .{
         "blame",
-        "--line-porcelain",
+        "--incremental",
         "HEAD",
         "--",
         arg.written(),

src/tui/editor.zig

@@ -1496,7 +1496,8 @@ pub const Editor = struct {
         const delta = self.get_delta_lines_until_row(row) orelse return;
         const head_line: i32 = delta + casted_row;
         if (head_line < 0) return;
-        const blame_name = self.buffer.?.get_line_blame(@intCast(head_line)) orelse return;
+        const commit = self.buffer.?.get_vcs_blame(@intCast(head_line)) orelse return;
+        const author = commit.author;
 
         self.plane.cursor_move_yx(@intCast(row), @intCast(col));
         self.render_diagnostic_cell(style);
@@ -1512,9 +1513,9 @@ pub const Editor = struct {
                 .right => {
                     const width = self.plane.window.width;
                     self.plane.cursor_move_yx(@intCast(row), @intCast(width -| (screen_width - space_begin) + 2));
-                    _ = self.plane.print("  {s}", .{blame_name}) catch 0;
+                    _ = self.plane.print("  {s}", .{author}) catch 0;
                 },
-                .left => _ = self.plane.print_aligned_right(@intCast(row), "  {s}", .{blame_name[0..@min(screen_width - space_begin - 3, blame_name.len)]}) catch {},
+                .left => _ = self.plane.print_aligned_right(@intCast(row), "  {s}", .{author[0..@min(screen_width - space_begin - 3, author.len)]}) catch {},
             }
         }
     }

src/tui/mainview.zig

@@ -2160,7 +2160,7 @@ pub fn vcs_blame_update(self: *Self, m: tp.message) void {
         buffer.set_vcs_blame(blame_info) catch {};
     } else if (m.match(.{ "PRJ", "git_blame", tp.extract(&file_path), tp.null_ }) catch return) {
         const buffer = self.buffer_manager.get_buffer_for_file(file_path) orelse return;
-        buffer.parse_git_blame() catch return;
+        buffer.parse_vcs_blame() catch return;
         if (self.get_editor_for_buffer(buffer)) |editor|
             editor.vcs_content_update() catch {};
     }