From 3141b936ee69f15f3a926b122d110b0940e152e0 Mon Sep 17 00:00:00 2001
From: Ben Lubas <56943754+benlubas@users.noreply.github.com>
Date: Wed, 29 Nov 2023 21:13:24 -0500
Subject: [PATCH] fix: truncate output text (#67)

---
 README.md                              | 1 +
 rplugin/python3/molten/options.py      | 2 ++
 rplugin/python3/molten/outputbuffer.py | 5 +++++
 3 files changed, 8 insertions(+)

diff --git a/README.md b/README.md
index 88ec8c8..75f3267 100644
--- a/README.md
+++ b/README.md
@@ -171,6 +171,7 @@ variable, their values, and a brief description.
 | `g:molten_output_win_style`                   | (`false`) \| `"minimal"`                                    | Value passed to the `style` option in `:h nvim_open_win()` |
 | `g:molten_save_path`                          | (`stdpath("data").."/molten"`) \| any path to a folder      | Where to save/load data with `:MoltenSave` and `:MoltenLoad` |
 | `g:molten_use_border_highlights`              | `true` \| (`false`)                                         | When true, uses different highlights for output border depending on the state of the cell (running, done, error). see [highlights](#highlights) |
+| `g:molten_limit_output_chars`                 | (`1000000`) \| int                                          | Limit on the number of chars in an output. If you're lagging your editor with too much output text, decrease it |
 | `g:molten_virt_lines_off_by_1`                | `true` \| (`false`)                                         | Allows the output window to cover exactly one line of the regular buffer when `output_virt_lines` is true, also effects `virt_text_output`. (useful for running code in a markdown file where that covered line will just be \`\`\`) |
 | `g:molten_virt_text_output`                   | `true` \| (`false`)                                         | When true, show output as virtual text below the cell. When true, output window doesn't open automatically on run. Effected by `virt_lines_off_by_1` |
 | `g:molten_virt_text_max_lines`                | (`12`) \| int                                               | Max height of the virtual text |
diff --git a/rplugin/python3/molten/options.py b/rplugin/python3/molten/options.py
index 52949a4..96648ad 100644
--- a/rplugin/python3/molten/options.py
+++ b/rplugin/python3/molten/options.py
@@ -35,6 +35,7 @@ class MoltenOptions:
     copy_output: bool
     enter_output_behavior: str
     image_provider: str
+    limit_output_chars: int
     output_crop_border: bool
     output_show_more: bool
     output_virt_lines: bool
@@ -68,6 +69,7 @@ def __init__(self, nvim: Nvim):
             ("molten_output_virt_lines", False),
             ("molten_output_win_border", [ "", "━", "", "" ]),
             ("molten_output_win_cover_gutter", True),
+            ("molten_limit_output_chars", 1000000),
             ("molten_output_win_hide_on_leave", True),
             ("molten_output_win_max_height", 999999),
             ("molten_output_win_max_width", 999999),
diff --git a/rplugin/python3/molten/outputbuffer.py b/rplugin/python3/molten/outputbuffer.py
index ba241e8..378dc47 100644
--- a/rplugin/python3/molten/outputbuffer.py
+++ b/rplugin/python3/molten/outputbuffer.py
@@ -147,6 +147,11 @@ def build_output_text(self, shape, buf: int, virtual: bool) -> Tuple[List[str],
                 lineno += chunktext.count("\n")
                 virtual_lines += virt_lines
 
+            limit = self.options.limit_output_chars
+            if limit and len(lines_str) > limit:
+                lines_str = lines_str[:limit]
+                lines_str += f"\n...truncated to {limit} chars\n"
+
             lines = handle_progress_bars(lines_str)
             lineno = len(lines) + virtual_lines
         else: