QtAutogen: Regenerate qrc files if their input changes (#15074)

Get dependencies from the output of ``rcc --list`` if using
Qt 5.  Otherwise process the file in the same way as the
qt4_add_resources macro.

This does not work for RCC files which are generated.

The cmake_autogen build step is implemented as a PRE_BUILD step
of the target currently if possible, rather than a standalone
custom target.  This is to keep the number of (synthesized)
custom targets that appear in the UI low, but in some cases
it is necessary to fall back to a full custom target.

Fall back to a full custom target for the VS builds if autorcc
is used.

5 files changed, 67 insertions, 0 deletions

diff --git a/Tests/QtAutogen/CMakeLists.txt b/Tests/QtAutogen/CMakeLists.txt
index 3fd00b8..a60b556 100644
--- a/Tests/QtAutogen/CMakeLists.txt
+++ b/Tests/QtAutogen/CMakeLists.txt
@@ -113,3 +113,35 @@ set_target_properties(no_link_language PROPERTIES AUTOMOC TRUE)
 qtx_wrap_cpp(uicOnlyMoc sub/uiconly.h)
 add_executable(uiconly sub/uiconly.cpp ${uicOnlyMoc})
 target_link_libraries(uiconly ${QT_LIBRARIES})
+
+try_compile(RCC_DEPENDS
+  "${CMAKE_CURRENT_BINARY_DIR}/autorcc_depends"
+  "${CMAKE_CURRENT_SOURCE_DIR}/autorcc_depends"
+  autorcc_depends
+  CMAKE_FLAGS "-DQT_QMAKE_EXECUTABLE:FILEPATH=${QT_QMAKE_EXECUTABLE}" "-DQT_TEST_VERSION=${QT_TEST_VERSION}"
+  OUTPUT_VARIABLE output
+)
+if (NOT RCC_DEPENDS)
+  message(SEND_ERROR "Initial build of autorcc_depends failed. Output: ${output}")
+endif()
+
+file(STRINGS "${CMAKE_CURRENT_BINARY_DIR}/autorcc_depends/info_file.txt" qrc_files)
+
+list(GET qrc_files 0 qrc_file1)
+
+set(timeformat "%Y%j%H%M%S")
+
+file(TIMESTAMP "${qrc_file1}" file1_before "${timeformat}")
+
+execute_process(COMMAND "${CMAKE_COMMAND}" -E sleep 1) # Ensure that the timestamp will change.
+execute_process(COMMAND "${CMAKE_COMMAND}" -E touch "${CMAKE_CURRENT_SOURCE_DIR}/autorcc_depends/res1_input.txt")
+
+execute_process(COMMAND "${CMAKE_COMMAND}" --build .
+  WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/autorcc_depends"
+)
+
+file(TIMESTAMP "${qrc_file1}" file1_step1 "${timeformat}")
+
+if (NOT file1_step1 GREATER file1_before)
+  message(SEND_ERROR "file1 (${qrc_file1}) should have changed in the first step!")
+endif()
diff --git a/Tests/QtAutogen/autorcc_depends/CMakeLists.txt b/Tests/QtAutogen/autorcc_depends/CMakeLists.txt
new file mode 100644
index 0000000..afd95bc
--- /dev/null
+++ b/Tests/QtAutogen/autorcc_depends/CMakeLists.txt
@@ -0,0 +1,24 @@
+cmake_minimum_required(VERSION 2.8)
+project(autorcc_depends)
+
+set(CMAKE_AUTORCC ON)
+
+if (QT_TEST_VERSION STREQUAL 4)
+  find_package(Qt4 REQUIRED)
+  set(QT_CORE_TARGET Qt4::QtCore)
+else()
+  if (NOT QT_TEST_VERSION STREQUAL 5)
+    message(SEND_ERROR "Invalid Qt version specified.")
+  endif()
+
+  find_package(Qt5Core REQUIRED)
+  set(QT_CORE_TARGET Qt5::Core)
+endif()
+
+add_executable(test_res1
+  test_res1.cpp
+  res1.qrc
+)
+target_link_libraries(test_res1 ${QT_CORE_TARGET})
+add_custom_command(TARGET test_res1 POST_BUILD COMMAND
+  ${CMAKE_COMMAND} -E echo "$<TARGET_FILE:test_res1>" > info_file.txt)
diff --git a/Tests/QtAutogen/autorcc_depends/res1.qrc b/Tests/QtAutogen/autorcc_depends/res1.qrc
new file mode 100644
index 0000000..cfea618
--- /dev/null
+++ b/Tests/QtAutogen/autorcc_depends/res1.qrc
@@ -0,0 +1,5 @@
+<RCC>
+    <qresource prefix="/">
+        <file>res1_input.txt</file>
+    </qresource>
+</RCC>
diff --git a/Tests/QtAutogen/autorcc_depends/res1_input.txt b/Tests/QtAutogen/autorcc_depends/res1_input.txt
new file mode 100644
index 0000000..da62762
--- /dev/null
+++ b/Tests/QtAutogen/autorcc_depends/res1_input.txt
@@ -0,0 +1 @@
+Res1 input.
diff --git a/Tests/QtAutogen/autorcc_depends/test_res1.cpp b/Tests/QtAutogen/autorcc_depends/test_res1.cpp
new file mode 100644
index 0000000..766b775
--- /dev/null
+++ b/Tests/QtAutogen/autorcc_depends/test_res1.cpp
@@ -0,0 +1,5 @@
+
+int main()
+{
+  return 0;
+}