From 1c978f7ec564ececef44d114c7ea82b01ff5fd14 Mon Sep 17 00:00:00 2001
From: David Adam <zanchey@ucc.gu.uwa.edu.au>
Date: Thu, 30 Mar 2023 12:01:23 +0800
Subject: [PATCH] cmake: add support for vendored cmake

Use a "cmake-vendored" directory if it exists, to avoid accessing the
network if it's available, and a target to create an appropriate tarball
to create that directory.
---
 cmake/Rust.cmake | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/cmake/Rust.cmake b/cmake/Rust.cmake
index b6137d812..0ce085779 100644
--- a/cmake/Rust.cmake
+++ b/cmake/Rust.cmake
@@ -1,15 +1,25 @@
-include(FetchContent)
+if(EXISTS "${CMAKE_SOURCE_DIR}/corrosion-vendor/")
+    add_subdirectory("${CMAKE_SOURCE_DIR}/corrosion-vendor/")
+else()
+    include(FetchContent)
 
-# Don't let Corrosion's tests interfere with ours.
-set(CORROSION_TESTS OFF CACHE BOOL "" FORCE)
+    # Don't let Corrosion's tests interfere with ours.
+    set(CORROSION_TESTS OFF CACHE BOOL "" FORCE)
 
-FetchContent_Declare(
-    Corrosion
-    GIT_REPOSITORY https://github.com/mqudsi/corrosion
-    GIT_TAG fish
-)
+    FetchContent_Declare(
+        Corrosion
+        GIT_REPOSITORY https://github.com/mqudsi/corrosion
+        GIT_TAG fish
+    )
 
-FetchContent_MakeAvailable(Corrosion)
+    FetchContent_MakeAvailable(Corrosion)
+
+    add_custom_target(corrosion-vendor.tar.gz
+        COMMAND git archive --format tar.gz --output "${CMAKE_BINARY_DIR}/corrosion-vendor.tar.gz"
+        --prefix corrosion-vendor/ HEAD
+        WORKING_DIRECTORY ${corrosion_SOURCE_DIR}
+    )
+endif()
 
 set(fish_rust_target "fish-rust")