source maps work for app code in `bun dev`!

1 files changed, 80 insertions, 0 deletions

diff --git a/src/string_joiner.zig b/src/string_joiner.zig
new file mode 100644
index 000000000..d49c32867
--- /dev/null
+++ b/src/string_joiner.zig
@@ -0,0 +1,80 @@
+/// Rope-like data structure for joining many small strings into one big string.
+const Joiner = @This();
+
+const string = @import("string_types.zig").string;
+const Allocator = @import("std").mem.Allocator;
+const assert = @import("std").debug.assert;
+const copy = @import("std").mem.copy;
+const Env = @import("./env.zig");
+const ObjectPool = @import("./pool.zig").ObjectPool;
+
+const default_allocator = @import("./global.zig").default_allocator;
+
+const Joinable = struct {
+    offset: u31 = 0,
+    needs_deinit: bool = false,
+    allocator: std.mem.Allocator = undefined,
+    slice: []const u8 = "",
+
+    pub const Pool = ObjectPool(Joinable, null, true, 4);
+};
+
+last_byte: u8 = 0,
+len: usize = 0,
+
+head: ?*Joinable.Pool.Node = null,
+tail: ?*Joinable.Pool.Node = null,
+
+pub fn done(this: *Joiner, allocator: std.mem.Allocator) ![]u8 {
+    var slice = try allocator.alloc(u8, this.cap);
+    var remaining = slice;
+    var el_ = this.head;
+    while (el_) |join| {
+        const to_join = join.data.slice[join.offset..];
+        @memcpy(remaining.ptr, to_join.ptr, to_join.len);
+
+        remaining = remaining[to_join.len..];
+
+        var prev = join;
+        el_ = join.next;
+        if (prev.data.needs_deinit) {
+            prev.data.allocator.free(join.data.slice);
+            prev.data = Joinable{};
+        }
+        prev.release();
+    }
+
+    return slice[0 .. slice.len - remaining.len];
+}
+
+pub fn lastByte(this: *const Joiner) u8 {
+    if (this.tail) |tail| {
+        const slice = tail.data.slice[tail.data.offset..];
+        return if (slice.len > 0) slice[slice.len - 1] else 0;
+    }
+
+    return 0;
+}
+
+pub fn append(this: *Joiner, slice: string, offset: u32, allocator: ?std.mem.Allocator) void {
+    const data = slice[offset..];
+    this.len += @truncate(u32, data.len);
+
+    var new_tail = Joinable.Pool.get(default_allocator);
+    new_tail.data = Joinable{
+        .offset = offset,
+        .allocator = allocator orelse undefined,
+        .needs_deinit = allocator != null,
+        .slice = slice,
+    };
+
+    var tail = this.tail orelse {
+        this.tail = new_tail;
+        this.head = new_tail;
+        return;
+    };
+    tail.next = new_tail;
+    this.tail = new_tail;
+}
+
+const std = @import("std");