1 files changed, 71 insertions, 0 deletions
diff --git a/Master/texmf-dist/scripts/extractbb/extractbb.lua b/Master/texmf-dist/scripts/extractbb/extractbb.lua
new file mode 100755
index 00000000000..15e9909fb70
--- /dev/null
+++ b/Master/texmf-dist/scripts/extractbb/extractbb.lua
@@ -0,0 +1,71 @@
+#!/usr/bin/env texlua
+-- extractbb-lua
+-- https://github.com/gucci-on-fleek/extractbb
+-- SPDX-License-Identifier: MPL-2.0+
+-- SPDX-FileCopyrightText: 2024 Max Chernoff
+--
+-- A wrapper script to allow you to choose which implementation of extractbb to
+-- use. Should hopefully be replaced with the ``scratch'' file in TeX Live 2025.
+--
+-- v1.0.0 (2024-11-17) %%version %%dashdate
+
+---------------------
+--- Configuration ---
+---------------------
+-- Choose which implementation of extractbb to use.
+local DEFAULT = "wrapper"
+
+
+-----------------
+--- Execution ---
+-----------------
+
+-- Get the value of the environment variable that decides which version to run.
+local env_choice = os.env["TEXLIVE_EXTRACTBB"]
+
+-- If the environment variable is set to a file path, run that directly.
+local env_mode = lfs.attributes(env_choice or "", "mode")
+if (env_mode == "file") or (env_mode == "link") then
+    arg[0] = env_choice
+    table.insert(arg, 1, env_choice)
+    arg[-1] = nil
+    return os.exec(arg)
+end
+
+-- Map the choice names to file names.
+kpse.set_program_name("texlua", "extractbb")
+local choice_mapping = {
+    wrapper = kpse.find_file("extractbb-wrapper.lua", "lua", true),
+    scratch = kpse.find_file("extractbb-scratch.lua", "lua", true),
+}
+
+-- Choose the implementation to run.
+local choice = choice_mapping[env_choice] or choice_mapping[DEFAULT]
+
+if not choice then
+    print("No implementation of extractbb found. Exiting.")
+    os.exit(1)
+end
+
+-- Make sure that the script is not writable.
+if kpse.out_name_ok_silent_extended(choice) then
+    if os.env["TEXLIVE_EXTRACTBB_UNSAFE"] == "unsafe" then
+        -- If we're running in development mode, then we can allow this.
+    else
+        print("Refusing to run a writable script. Exiting.")
+        os.exit(1)
+    end
+end
+
+-- Make sure that the script is beside this one, just to be safe
+local split_dir_pattern = "^(.*)[/\\]([^/\\]-)$"
+local current_dir, current_name = arg[0]:match(split_dir_pattern)
+local choice_dir, choice_name = choice:match(split_dir_pattern)
+
+if current_dir ~= choice_dir then
+    print("Refusing to run a script from a different directory. Exiting.")
+    os.exit(1)
+end
+
+-- And run it.
+dofile(choice)