Add fallback to old behavior on diff failure
This commit is contained in:
Jeffery Stager
parent
4e33e1d61f
commit
254353a9f4
@ -2214,9 +2214,25 @@ fn formattingHandler(server: *Server, writer: anytype, id: types.RequestId, req:
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.Exited => |code| if (code == 0) {
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if (std.mem.eql(u8, handle.document.text, stdout_bytes)) return try respondGeneric(writer, id, null_result_response);
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var edits = try diff.edits(server.allocator, handle.document.text, stdout_bytes);
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defer edits.deinit();
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defer for (edits.items) |item| item.newText.deinit();
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var edits = diff.edits(server.allocator, handle.document.text, stdout_bytes) catch {
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// If there was an error trying to diff the text, return the formatted response
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// as the new text for the entire range of the document
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return try send(writer, server.arena.allocator(), types.Response{
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.id = id,
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.result = .{
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.TextEdits = &[1]types.TextEdit{
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.{
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.range = try offsets.documentRange(handle.document, server.offset_encoding),
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.newText = stdout_bytes,
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},
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},
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},
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});
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};
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defer {
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for (edits.items) |item| item.newText.deinit();
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edits.deinit();
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}
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var text_edits = try std
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.ArrayList(types.TextEdit)
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@ -2234,18 +2250,11 @@ fn formattingHandler(server: *Server, writer: anytype, id: types.RequestId, req:
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.TextEdits = text_edits.items,
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};
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return try send(writer, server.arena.allocator(), types.Response{
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.id = id,
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.result = result,
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// .result = .{
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// .TextEdits = &[1]types.TextEdit{
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// .{
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// .range = try offsets.documentRange(handle.document, server.offset_encoding),
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// .newText = stdout_bytes,
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// },
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// },
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// },
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});
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return try send(
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writer,
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server.arena.allocator(),
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types.Response{ .id = id, .result = result },
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);
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},
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else => {},
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}
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79
src/diff.zig
79
src/diff.zig
@ -1,14 +1,18 @@
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const std = @import("std");
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const types = @import("types.zig");
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// pub const Position = struct { line: usize, character: usize };
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// pub const Range = struct { start: Position, end: Position };
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// This is essentially the same as `types.TextEdit`, but we use an
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// ArrayList(u8) here to be able to clean up the memory later on
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pub const Edit = struct {
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range: types.Range,
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newText: std.ArrayList(u8),
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};
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// Whether the `Change` is an addition, deletion, or no change from the
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// original string to the new string
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const Operation = enum { Deletion, Addition, Nothing };
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/// A single character difference between two strings
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const Change = struct {
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operation: Operation,
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pos: usize,
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@ -68,18 +72,45 @@ fn trim_input(a_out: *[]const u8, b_out: *[]const u8) usize {
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}) {}
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end -= 1;
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// Sanity check to make sure our range isn't negative
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if (start < a.len - end and start < b.len - end) {
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a_out.* = a[start .. a.len - end];
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b_out.* = b[start .. b.len - end];
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var a_start = start;
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var a_end = a.len - end;
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var b_start = start;
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var b_end = b.len - end;
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// In certain situations, the trimmed range can be "negative" where
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// `a_start` ends up being after `a_end` in the byte stream. If you
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// consider the following inputs:
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// a: "xx gg xx"
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// b: "xx gg xx"
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//
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// This will lead to the following calculations:
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// a_start: 4
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// a_end: 4
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// b_start: 4
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// b_end: 2
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//
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// In negative range situations, we add the absolute value of the
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// the negative range's length (`b_start - b_end` in this case) to the
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// other range's length (a_end + (b_start - b_end)), and then set the
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// negative range end to the negative range start (b_end = b_start)
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if (a_start > a_end) {
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const difference = a_start - a_end;
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a_end = a_start;
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b_end += difference;
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}
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if (b_start > b_end) {
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const difference = b_start - b_end;
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b_end = b_start;
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a_end += difference;
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}
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a_out.* = a[a_start..a_end];
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b_out.* = b[b_start..b_end];
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return start;
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}
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a_out.* = a_out.*;
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b_out.* = b_out.*;
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return 0;
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}
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/// A 2D array that is addressable as a[row, col]
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pub const Array2D = struct {
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const Self = @This();
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@ -112,6 +143,7 @@ pub const Array2D = struct {
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}
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};
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/// Build a Longest Common Subsequence table
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fn calculate_lcs(
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lcs: *Array2D,
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astr: []const u8,
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@ -122,6 +154,13 @@ fn calculate_lcs(
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std.mem.set(usize, lcs.data[0 .. rows * cols], 0);
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// This approach is a dynamic programming technique to calculate the
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// longest common subsequence between two strings, `a` and `b`. We start
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// at 1 for `i` and `j` because the first column and first row are always
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// set to zero
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//
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// You can find more information about this at the following url:
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// https://en.wikipedia.org/wiki/Longest_common_subsequence_problem
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var i: usize = 1;
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while (i < rows) : (i += 1) {
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var j: usize = 1;
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@ -146,6 +185,8 @@ pub fn get_changes(
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b_trim: []const u8,
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allocator: std.mem.Allocator,
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) !std.ArrayList(Edit) {
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// First we get a list of changes between strings at the character level:
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// "addition", "deletion", and "no change" for each character
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var changes = try std.ArrayList(Change).initCapacity(allocator, a_trim.len);
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defer changes.deinit();
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try recur_changes(
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@ -157,6 +198,9 @@ pub fn get_changes(
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@intCast(i64, b_trim.len),
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);
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// We want to group runs of deletions and additions, and separate them by
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// runs of `.Nothing` changes. This will allow us to calculate the
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// `TextEdit` ranges
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var groups = std.ArrayList([]Change).init(allocator);
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defer groups.deinit();
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var active_change: ?[]Change = null;
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@ -181,6 +225,8 @@ pub fn get_changes(
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try groups.append(ac.*);
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}
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// The LCS algorithm works "in reverse", so we're putting everything back
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// in ascending order
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var a_lines = std.mem.split(u8, a, "\n");
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std.mem.reverse([]Change, groups.items);
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for (groups.items) |group| std.mem.reverse(Change, group);
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@ -188,6 +234,7 @@ pub fn get_changes(
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var edit_results = std.ArrayList(Edit).init(allocator);
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errdefer edit_results.deinit();
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// Convert our grouped changes into `Edit`s
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for (groups.items) |group| {
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var range_start = group[0].pos;
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var range_len: usize = 0;
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@ -224,6 +271,10 @@ fn recur_changes(
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i: i64,
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j: i64,
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) anyerror!void {
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// This function recursively works backwards through the LCS table in
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// order to figure out what kind of changes took place to transform `a`
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// into `b`
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const ii = @intCast(usize, i);
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const jj = @intCast(usize, j);
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@ -282,15 +333,15 @@ fn char_pos_to_range(
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}
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if (result_start_pos == null) return error.InvalidRange;
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// If we did not find an end position, it is outside the range of the
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// string for some reason so clamp it to the string end position
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if (result_end_pos == null) {
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result_end_pos = types.Position{
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.line = @intCast(i64, line_pos),
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.character = @intCast(i64, char_pos),
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};
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}
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if (result_start_pos == null or result_end_pos == null) {
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return error.InvalidRange;
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}
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return types.Range{
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.start = result_start_pos.?,
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