From bd1f6ced7166d213bf8d99ea86d63c1430f00033 Mon Sep 17 00:00:00 2001
From: mid-kid <esteve.varela@gmail.com>
Date: Tue, 6 Dec 2022 23:59:43 +0100
Subject: [PATCH] CMake: Allow building with external crc32c

Ported from gentoo: https://github.com/gentoo/gentoo/blob/795a0a5/media-libs/tg_owt/files/tg_owt-0_pre20220507-unbundle-crc32c.patch
---
 CMakeLists.txt           |  6 ++++--
 cmake/external.cmake     | 14 ++++++++++++++
 cmake/libcrc32c.cmake    |  4 +++-
 cmake/tg_owtConfig.cmake |  5 ++++-
 4 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4d3f674f..19f97000 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -139,7 +139,6 @@ set_target_properties(tg_owt PROPERTIES SOVERSION 0 VERSION 0.0.0)
 
 target_link_libraries(tg_owt
 PRIVATE
-    tg_owt::libcrc32c
     tg_owt::libpffft
     tg_owt::librnnoise
     tg_owt::libsrtp
@@ -177,6 +176,7 @@ link_opus(tg_owt)
 link_libabsl(tg_owt)
 link_libopenh264(tg_owt)
 link_libvpx(tg_owt)
+link_crc32c(tg_owt)
 
 if (TG_OWT_BUILD_AUDIO_BACKENDS AND (UNIX AND NOT APPLE))
     link_libalsa(tg_owt)
@@ -2627,7 +2627,6 @@ endif()
 
 set(export_targets
     ${tg_owt_export}
-    libcrc32c
     libpffft
     librnnoise
     libsrtp
@@ -2645,6 +2644,9 @@ endif()
 if (NOT LIBOPENH264_FOUND)
     list(APPEND export_targets libopenh264)
 endif()
+if (NOT Crc32c_FOUND)
+    list(APPEND export_targets libcrc32c)
+endif()
 
 export(
     TARGETS ${export_targets}
diff --git a/cmake/external.cmake b/cmake/external.cmake
index 9328861e..6c4aa752 100644
--- a/cmake/external.cmake
+++ b/cmake/external.cmake
@@ -166,6 +166,20 @@ function(link_libvpx target_name)
     endif()
 endfunction()
 
+# crc32c
+function(link_crc32c target_name)
+    if (TG_OWT_PACKAGED_BUILD)
+        find_package(Crc32c)
+        set(Crc32c_FOUND ${Crc32c_FOUND} PARENT_SCOPE)
+        if (Crc32c_FOUND)
+            target_link_libraries(${target_name} INTERFACE Crc32c::crc32c)
+        endif()
+    endif()
+    if (NOT Crc32c_FOUND)
+        target_link_libraries(${target_name} PRIVATE tg_owt::libcrc32c)
+    endif()
+endfunction()
+
 function(link_glib target_name)
     find_package(PkgConfig REQUIRED)
     pkg_check_modules(GLIB2 REQUIRED glib-2.0)
diff --git a/cmake/libcrc32c.cmake b/cmake/libcrc32c.cmake
index 9e1643ae..42d2d1cd 100644
--- a/cmake/libcrc32c.cmake
+++ b/cmake/libcrc32c.cmake
@@ -28,6 +28,8 @@ target_sources(libcrc32c PRIVATE ${PROJECT_BINARY_DIR}/include/crc32c/crc32c_con
 
 target_include_directories(libcrc32c
 PRIVATE
-    ${libcrc32c_loc}/include
     ${PROJECT_BINARY_DIR}/include
+PUBLIC
+    $<BUILD_INTERFACE:${libcrc32c_loc}/include>
+    $<INSTALL_INTERFACE:${webrtc_includedir}/third_party/crc32c/src/include>
 )
diff --git a/cmake/tg_owtConfig.cmake b/cmake/tg_owtConfig.cmake
index e9f43880..431deaf4 100644
--- a/cmake/tg_owtConfig.cmake
+++ b/cmake/tg_owtConfig.cmake
@@ -1,6 +1,9 @@
+include(CMakeFindDependencyMacro)
 if (@absl_FOUND@)
-    include(CMakeFindDependencyMacro)
     find_dependency(absl REQUIRED)
 endif()
+if (@Crc32c_FOUND@)
+    find_dependency(Crc32c)
+endif()
 
 include("${CMAKE_CURRENT_LIST_DIR}/tg_owtTargets.cmake")