FindLibb2: Don't rely solely on pkg-config

Task-number: QTBUG-86283
Change-Id: Ie455d7cfc6e6f9ae8297f8bc0daf2816ccce91b6
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

cmake/FindLibb2.cmake

@@ -1,7 +1,37 @@
+# Blake2 contains a reference implementation, libb2 is a more efficient
+# implementation of a subset of Blake2 functions and should be preferred.
+# This Find module only searches for libb2 for that reason.
+
+if(TARGET Libb2::Libb2)
+    set(Libb2_FOUND TRUE)
+    return()
+endif()
+
 find_package(PkgConfig QUIET)
 
-pkg_check_modules(Libb2 libb2 IMPORTED_TARGET)
+if(PkgConfig_FOUND)
+    pkg_check_modules(Libb2 libb2 IMPORTED_TARGET)
 
-if (NOT TARGET PkgConfig::Libb2)
-    set(Libb2_FOUND 0)
+    if (TARGET PkgConfig::Libb2)
+        add_library(Libb2::Libb2 INTERFACE IMPORTED)
+        target_link_libraries(Libb2::Libb2 INTERFACE PkgConfig::Libb2)
+        set(Libb2_FOUND TRUE)
+    endif()
+else()
+    find_path(LIBB2_INCLUDE_DIR NAMES blake2.h)
+    find_library(LIBB2_LIBRARY NAMES b2)
+
+    if(LIBB2_LIBRARY AND LIBB2_INCLUDE_DIR)
+        add_library(Libb2::Libb2 UNKNOWN IMPORTED)
+        set_target_properties(Libb2::Libb2 PROPERTIES
+            IMPORTED_LOCATION ${LIBB2_LIBRARY}
+            INTERFACE_INCLUDE_DIRECTORIES ${LIBB2_INCLUDE_DIR}
+        )
+    endif()
+
+    include(FindPackageHandleStandardArgs)
+    find_package_handle_standard_args(Libb2 REQUIRED_VARS
+        LIBB2_LIBRARY
+        LIBB2_INCLUDE_DIR
+    )
 endif()

src/corelib/CMakeLists.txt

@@ -756,7 +756,7 @@ qt_internal_extend_target(Core CONDITION QT_FEATURE_doubleconversion AND NOT QT_
 
 qt_internal_extend_target(Core CONDITION QT_FEATURE_system_libb2
     LIBRARIES
-        PkgConfig::Libb2
+        Libb2::Libb2
 )
 
 qt_internal_extend_target(Core CONDITION QT_FEATURE_easingcurve

src/corelib/configure.cmake

@@ -22,7 +22,7 @@ if(QT_FEATURE_dlopen)
 endif()
 qt_find_package(Libsystemd PROVIDED_TARGETS PkgConfig::Libsystemd MODULE_NAME core QMAKE_LIB journald)
 qt_find_package(WrapAtomic PROVIDED_TARGETS WrapAtomic::WrapAtomic MODULE_NAME core QMAKE_LIB libatomic)
-qt_find_package(Libb2 PROVIDED_TARGETS PkgConfig::Libb2 MODULE_NAME core QMAKE_LIB libb2)
+qt_find_package(Libb2 PROVIDED_TARGETS Libb2::Libb2 MODULE_NAME core QMAKE_LIB libb2)
 qt_find_package(WrapRt PROVIDED_TARGETS WrapRt::WrapRt MODULE_NAME core QMAKE_LIB librt)
 qt_find_package(LTTngUST PROVIDED_TARGETS LTTng::UST MODULE_NAME core QMAKE_LIB lttng-ust)
 qt_add_qmake_lib_dependency(lttng-ust libdl)

src/corelib/configure.json

@@ -119,7 +119,8 @@
             },
             "headers": "blake2.h",
             "sources": [
-                { "type": "pkgConfig", "args": "libb2" }
+                { "type": "pkgConfig", "args": "libb2" },
+                "-lb2"
             ]
         },
         "librt": {

util/cmake/helper.py

@@ -440,7 +440,7 @@ _library_map = [
     LibraryMapping("journald", "Libsystemd", "PkgConfig::Libsystemd"),
     LibraryMapping("jpeg", "JPEG", "JPEG::JPEG"),  # see also libjpeg
     LibraryMapping("libatomic", "WrapAtomic", "WrapAtomic::WrapAtomic"),
-    LibraryMapping("libb2", "Libb2", "PkgConfig::Libb2"),
+    LibraryMapping("libb2", "Libb2", "Libb2::Libb2"),
     LibraryMapping("libclang", "WrapLibClang", "WrapLibClang::WrapLibClang"),
     LibraryMapping("libdl", None, "${CMAKE_DL_LIBS}"),
     LibraryMapping("libinput", "Libinput", "Libinput::Libinput"),