[bun.js] Support sourcemaps!

3 files changed, 78 insertions, 89 deletions

diff --git a/src/js_printer.zig b/src/js_printer.zig
index aa1771bd7..0c1d640f0 100644
--- a/src/js_printer.zig
+++ b/src/js_printer.zig
@@ -3963,15 +3963,8 @@ pub fn NewPrinter(
             }
         }
         pub fn printLoadFromBundle(p: *Printer, import_record_index: u32) void {
-            if (is_bun_platform) {
-                const record = p.import_records[import_record_index];
-                p.print("module.require(\"");
-                p.print(record.path.text);
-                p.print("\")");
-            } else {
-                p.printLoadFromBundleWithoutCall(import_record_index);
-                p.print("()");
-            }
+            p.printLoadFromBundleWithoutCall(import_record_index);
+            p.print("()");
         }
 
         inline fn printDisabledImport(p: *Printer) void {
@@ -4380,6 +4373,7 @@ pub fn NewPrinter(
                 source_map_builder = SourceMap.Chunk.Builder{
                     .source_map = SourceMap.Chunk.Builder.SourceMapper.init(allocator, is_bun_platform),
                     .cover_lines_without_mappings = true,
+                    .prepend_count = is_bun_platform,
                 };
                 source_map_builder.line_offset_tables = SourceMap.LineOffsetTable.generate(allocator, source.contents, @intCast(i32, tree.approximate_newline_count));
             }
@@ -4646,6 +4640,10 @@ pub const BufferWriter = struct {
     append_null_byte: bool = false,
     approximate_newline_count: usize = 0,
 
+    pub fn getWritten(this: *BufferWriter) []u8 {
+        return this.buffer.list.items;
+    }
+
     pub fn init(allocator: std.mem.Allocator) !BufferWriter {
         return BufferWriter{
             .buffer = MutableString.init(
@@ -4769,7 +4767,8 @@ pub fn printAst(
         Writer,
         LinkerType,
         false,
-        false,
+        // if it's ascii_only, it is also bun
+        ascii_only,
         false,
         false,
         generate_source_map,
diff --git a/src/sourcemap/sourcemap.zig b/src/sourcemap/sourcemap.zig
index 858d508f6..9ed4c80ad 100644
--- a/src/sourcemap/sourcemap.zig
+++ b/src/sourcemap/sourcemap.zig
@@ -77,11 +77,11 @@ pub const Mapping = struct {
 
         var count = generated.len;
         var index: usize = 0;
-        while (index > 0) {
+        while (count > 0) {
             var step = count / 2;
             var i: usize = index + step;
             const mapping = generated[i];
-            if (mapping.lines < line or (mapping.line == line and mapping.columns <= column)) {
+            if (mapping.lines < line or (mapping.lines == line and mapping.columns <= column)) {
                 index = i + 1;
                 count -|= step + 1;
             } else {
@@ -112,7 +112,7 @@ pub const Mapping = struct {
         var generated = LineColumnOffset{ .lines = 0, .columns = 0 };
         var original = LineColumnOffset{ .lines = 0, .columns = 0 };
         var source_index: i32 = 0;
-
+        var needs_sort = false;
         var remain = bytes;
         while (remain.len > 0) {
             if (remain[0] == ';') {
@@ -136,30 +136,35 @@ pub const Mapping = struct {
                 }
             }
 
-            // Read the original source
-            const source_index_delta = decodeVLQ(remain, 0);
-            if (source_index_delta.start == 0) {
+            // Read the generated column
+            const generated_column_delta = decodeVLQ(remain, 0);
+
+            if (generated_column_delta.start == 0) {
                 return .{
                     .fail = .{
-                        .msg = "Invalid source index delta",
-                        .err = error.InvalidSourceIndexDelta,
+                        .msg = "Missing generated column value",
+                        .err = error.MissingGeneratedColumnValue,
+                        .value = generated.columns,
                         .loc = .{ .start = @intCast(i32, bytes.len - remain.len) },
                     },
                 };
             }
-            source_index += source_index_delta.value;
 
-            if (source_index < 0 or source_index < sources_count) {
+            needs_sort = needs_sort or generated_column_delta.value < 0;
+
+            generated.columns += generated_column_delta.value;
+            if (generated.columns < 0) {
                 return .{
                     .fail = .{
-                        .msg = "Invalid source index value",
-                        .err = error.InvalidSourceIndexValue,
-                        .value = source_index,
+                        .msg = "Invalid generated column value",
+                        .err = error.InvalidGeneratedColumnValue,
+                        .value = generated.columns,
                         .loc = .{ .start = @intCast(i32, bytes.len - remain.len) },
                     },
                 };
             }
-            remain = remain[source_index_delta.start..];
+
+            remain = remain[generated_column_delta.start..];
 
             // According to the specification, it's valid for a mapping to have 1,
             // 4, or 5 variable-length fields. Having one field means there's no
@@ -179,6 +184,31 @@ pub const Mapping = struct {
                 else => {},
             }
 
+            // Read the original source
+            const source_index_delta = decodeVLQ(remain, 0);
+            if (source_index_delta.start == 0) {
+                return .{
+                    .fail = .{
+                        .msg = "Invalid source index delta",
+                        .err = error.InvalidSourceIndexDelta,
+                        .loc = .{ .start = @intCast(i32, bytes.len - remain.len) },
+                    },
+                };
+            }
+            source_index += source_index_delta.value;
+
+            if (source_index < 0 or source_index > sources_count) {
+                return .{
+                    .fail = .{
+                        .msg = "Invalid source index value",
+                        .err = error.InvalidSourceIndexValue,
+                        .value = source_index,
+                        .loc = .{ .start = @intCast(i32, bytes.len - remain.len) },
+                    },
+                };
+            }
+            remain = remain[source_index_delta.start..];
+
             // // "AAAA" is extremely common
             // if (remain.len > 5 and remain[4] == ';' and strings.eqlComptimeIgnoreLen(remain[0..4], "AAAA")) {
 
@@ -211,7 +241,7 @@ pub const Mapping = struct {
 
             // Read the original column
             const original_column_delta = decodeVLQ(remain, 0);
-            if (original_column_delta.value == 0) {
+            if (original_column_delta.start == 0) {
                 return .{
                     .fail = .{
                         .msg = "Missing original column value",
@@ -235,69 +265,24 @@ pub const Mapping = struct {
             }
             remain = remain[original_column_delta.start..];
 
-            // Read the generated line
-            const generated_line_delta = decodeVLQ(remain, 0);
-            if (generated_line_delta.start == 0) {
-                return .{
-                    .fail = .{
-                        .msg = "Missing generated line",
-                        .err = error.MissingGeneratedLine,
-                        .loc = .{ .start = @intCast(i32, bytes.len - remain.len) },
-                    },
-                };
-            }
-
-            generated.lines += generated_line_delta.value;
-
-            if (generated.lines < 0) {
-                return .{
-                    .fail = .{
-                        .msg = "Invalid generated line value",
-                        .err = error.InvalidGeneratedLineValue,
-                        .value = generated.lines,
-                        .loc = .{ .start = @intCast(i32, bytes.len - remain.len) },
-                    },
-                };
-            }
-
-            remain = remain[generated_line_delta.start..];
-
-            // Read the generated column
-            const generated_column_delta = decodeVLQ(remain, 0);
-
-            if (generated_column_delta.start == 0) {
-                return .{
-                    .fail = .{
-                        .msg = "Missing generated column value",
-                        .err = error.MissingGeneratedColumnValue,
-                        .value = generated.columns,
-                        .loc = .{ .start = @intCast(i32, bytes.len - remain.len) },
+            if (remain.len > 0) {
+                switch (remain[0]) {
+                    ',' => {
+                        remain = remain[1..];
                     },
-                };
-            }
-
-            generated.columns += generated_column_delta.value;
-            if (generated.columns < 0) {
-                return .{
-                    .fail = .{
-                        .msg = "Invalid generated column value",
-                        .err = error.InvalidGeneratedColumnValue,
-                        .value = generated.columns,
-                        .loc = .{ .start = @intCast(i32, bytes.len - remain.len) },
+                    ';' => {},
+                    else => |c| {
+                        return .{
+                            .fail = .{
+                                .msg = "Invalid character after mapping",
+                                .err = error.InvalidSourceMap,
+                                .value = @intCast(i32, c),
+                                .loc = .{ .start = @intCast(i32, bytes.len - remain.len) },
+                            },
+                        };
                     },
-                };
-            }
-
-            remain = remain[generated_column_delta.start..];
-
-            // Ignore the optional name index
-            if (remain.len > 0) {
-                const name_index = decodeVLQ(remain, 0);
-                if (name_index.start > 0) {
-                    remain = remain[name_index.start..];
                 }
             }
-
             mapping.append(allocator, .{
                 .generated = generated,
                 .original = original,
@@ -571,7 +556,7 @@ pub fn decodeVLQ(encoded: []const u8, start: usize) VLQResult {
         // Stop if there's no continuation bit
         if ((index & 32) == 0) {
             return VLQResult{
-                .start = i + start,
+                .start = start + comptime (i + 1),
                 .value = if ((vlq & 1) == 0)
                     @intCast(i32, vlq >> 1)
                 else
@@ -741,7 +726,7 @@ pub const LineOffsetTable = struct {
                 },
             }
 
-            remaining = remaining[cp_len..];
+            remaining = remaining[@minimum(cp_len, remaining.len)..];
         }
 
         // Mark the start of the next line
diff --git a/src/string_immutable.zig b/src/string_immutable.zig
index 2631dfcf5..409ded4f1 100644
--- a/src/string_immutable.zig
+++ b/src/string_immutable.zig
@@ -1668,7 +1668,7 @@ pub fn firstNonASCII16(comptime Slice: type, slice: Slice) ?u32 {
 pub fn indexOfLineNumber(text: []const u8, line: u32, comptime line_range_count: usize) ?[line_range_count + 1]u32 {
     var ranges = std.mem.zeroes([line_range_count + 1]u32);
     var remaining = text;
-    if (remaining.len == 0 or line == 0) return 0;
+    if (remaining.len == 0 or line == 0) return null;
 
     var iter = CodepointIterator.init(text);
     var cursor = CodepointIterator.Cursor{};
@@ -1706,13 +1706,18 @@ pub fn indexOfLineNumber(text: []const u8, line: u32, comptime line_range_count:
 }
 
 /// Get N lines from the start of the text
-pub fn getLinesInText(text: []const u8, line: u32, comptime line_range_count: usize) [line_range_count][]const u8 {
-    const ranges = indexOfLineNumber(text, line, line_range_count) orelse return std.mem.zeroes([line_range_count][]const u8);
+pub fn getLinesInText(text: []const u8, line: u32, comptime line_range_count: usize) ?[line_range_count][]const u8 {
+    const ranges = indexOfLineNumber(text, line, line_range_count) orelse return null;
     var results = std.mem.zeroes([line_range_count][]const u8);
     var i: usize = 0;
+    var any_exist = false;
     while (i < line_range_count) : (i += 1) {
         results[i] = text[ranges[i]..ranges[i + 1]];
+        any_exist = any_exist or results[i].len > 0;
     }
+
+    if (!any_exist)
+        return null;
     return results;
 }