feat: support loading extreamly large files

- Allocate initial file and leaf data outside of Buffer.arena
- Disable gutter diffs for very large files
- Disable syntax highlighting for very large files

src/buffer/Buffer.zig

@@ -28,6 +28,8 @@ arena: std.heap.ArenaAllocator,
 a: Allocator,
 external_a: Allocator,
 root: Root,
+leaves_buf: ?[]Node = null,
+file_buf: ?[]const u8 = null,
 file_path: []const u8 = "",
 last_save: ?Root = null,
 file_exists: bool = true,
@@ -1023,6 +1025,8 @@ pub fn create(a: Allocator) !*Self {
 }
 
 pub fn deinit(self: *Self) void {
+    if (self.file_buf) |buf| self.external_a.free(buf);
+    if (self.leaves_buf) |buf| self.external_a.free(buf);
     self.arena.deinit();
     self.external_a.destroy(self);
 }
@@ -1034,8 +1038,10 @@ fn new_file(self: *const Self, file_exists: *bool) !Root {
 
 pub fn load(self: *const Self, reader: anytype, size: usize) !Root {
     const eol = '\n';
-    var buf = try self.a.alloc(u8, size);
-    const read_size = try reader.read(buf);
+    var buf = try self.external_a.alloc(u8, size);
+    const self_ = @constCast(self);
+    self_.file_buf = buf;
+    const read_size = try reader.readAll(buf);
     if (read_size != size)
         return error.BufferUnderrun;
     const final_read = try reader.read(buf);
@@ -1047,7 +1053,8 @@ pub fn load(self: *const Self, reader: anytype, size: usize) !Root {
         if (buf[i] == eol) leaf_count += 1;
     }
 
-    var leaves = try self.a.alloc(Node, leaf_count);
+    var leaves = try self.external_a.alloc(Node, leaf_count);
+    self_.leaves_buf = leaves;
     var cur_leaf: usize = 0;
     var b: usize = 0;
     for (0..buf.len) |i| {

src/main.zig

@@ -13,6 +13,9 @@ const c = @cImport({
 const build_options = @import("build_options");
 const log = @import("log");
 
+pub var max_diff_lines: usize = 50000;
+pub var max_syntax_lines: usize = 50000;
+
 pub const application_name = "flow";
 pub const application_logo = "󱞏 ";
 

src/tui/editor.zig

@@ -10,6 +10,7 @@ const text_manip = @import("text_manip");
 const syntax = @import("syntax");
 const project_manager = @import("project_manager");
 const CaseData = @import("CaseData");
+const root_mod = @import("root");
 
 const Plane = @import("renderer").Plane;
 const Cell = @import("renderer").Cell;
@@ -403,17 +404,21 @@ pub const Editor = struct {
         if (self.buffer) |_| try self.close();
         self.buffer = new_buf;
 
+        self.syntax = syntax: {
+            if (new_buf.root.lines() > root_mod.max_syntax_lines)
+                break :syntax null;
+            const lang_override = tp.env.get().str("language");
             var content = std.ArrayList(u8).init(self.a);
             defer content.deinit();
             try new_buf.root.store(content.writer());
-        self.syntax = syntax: {
-            const lang_override = tp.env.get().str("language");
-            if (lang_override.len > 0)
-                break :syntax syntax.create_file_type(self.a, content.items, lang_override) catch null;
-            break :syntax syntax.create_guess_file_type(self.a, content.items, self.file_path) catch null;
+            const syn = if (lang_override.len > 0)
+                syntax.create_file_type(self.a, content.items, lang_override) catch null
+            else
+                syntax.create_guess_file_type(self.a, content.items, self.file_path) catch null;
+            if (syn) |syn_|
+                project_manager.did_open(file_path, syn_.file_type, self.lsp_version, try content.toOwnedSlice()) catch {};
+            break :syntax syn;
         };
-        if (self.syntax) |syn|
-            project_manager.did_open(file_path, syn.file_type, self.lsp_version, try content.toOwnedSlice()) catch {};
 
         const ftn = if (self.syntax) |syn| syn.file_type.name else "text";
         const fti = if (self.syntax) |syn| syn.file_type.icon else "🖹";
@@ -2907,6 +2912,8 @@ pub const Editor = struct {
         defer frame.deinit();
         const root = try self.buf_root();
         const token = @intFromPtr(root);
+        if (root.lines() > root_mod.max_syntax_lines)
+            return;
         if (self.syntax_token == token)
             return;
         if (self.syntax) |syn| {

src/tui/editor_gutter.zig

@@ -300,6 +300,10 @@ fn mouse_click_button5(_: *Self) error{Exit}!bool {
 }
 
 fn diff_update(self: *Self) !void {
+    if (self.lines > root.max_diff_lines) {
+        self.diff_symbols_clear();
+        return;
+    }
     const editor = self.editor;
     const new = if (editor.get_current_root()) |new| new else return;
     const old = if (editor.buffer) |buffer| if (buffer.last_save) |old| old else return else return;