ENH: Added FindPackageMessage module

- Defines FIND_PACKAGE_MESSAGE function to help display
    find result messages only once
  - Added use of it to FindPackageHandleStandardArgs
  - Added use of it to FindQt4, and FindX11
  - This cleans up repeated messages in big projects

Modules/FindPackageHandleStandardArgs.cmake

@@ -17,6 +17,7 @@
 #    be "Could NOT find LibXml2", if you don't like this message you can specify
 #    your own custom failure message there.
 
+INCLUDE(FindPackageMessage)
 FUNCTION(FIND_PACKAGE_HANDLE_STANDARD_ARGS _NAME _FAIL_MSG _VAR1 )
 
   IF("${_FAIL_MSG}" STREQUAL "DEFAULT_MSG")
@@ -27,22 +28,25 @@ FUNCTION(FIND_PACKAGE_HANDLE_STANDARD_ARGS _NAME _FAIL_MSG _VAR1 )
 
   STRING(TOUPPER ${_NAME} _NAME_UPPER)
 
+  SET(DETAILS "")
   SET(${_NAME_UPPER}_FOUND TRUE)
   IF(NOT ${_VAR1})
     SET(${_NAME_UPPER}_FOUND FALSE)
+  ELSE(NOT ${_VAR1})
+    SET(DETAILS "${DETAILS}[${${_VAR1}}]")
   ENDIF(NOT ${_VAR1})
 
   # check if all passed variables are valid
   FOREACH(_CURRENT_VAR ${ARGN})
     IF(NOT ${_CURRENT_VAR})
       SET(${_NAME_UPPER}_FOUND FALSE)
+    ELSE(NOT ${_CURRENT_VAR})
+      SET(DETAILS "${DETAILS}[${${_CURRENT_VAR}}]")
     ENDIF(NOT ${_CURRENT_VAR})
   ENDFOREACH(_CURRENT_VAR)
 
   IF (${_NAME_UPPER}_FOUND)
-    IF (NOT ${_NAME}_FIND_QUIETLY)
-        MESSAGE(STATUS "Found ${_NAME}: ${${_VAR1}}")
-    ENDIF (NOT ${_NAME}_FIND_QUIETLY)
+    FIND_PACKAGE_MESSAGE(${_NAME} "Found ${_NAME}: ${${_VAR1}}" "${DETAILS}")
   ELSE (${_NAME_UPPER}_FOUND)
     IF (${_NAME}_FIND_REQUIRED)
         MESSAGE(FATAL_ERROR "${_FAIL_MESSAGE}")

Modules/FindPackageMessage.cmake

@@ -0,0 +1,35 @@
+# FIND_PACKAGE_MESSAGE(<name> "message for user" "find result details")
+#
+# This macro is intended to be used in FindXXX.cmake modules files.
+# It will print a message once for each unique find result.
+# This is useful for telling the user where a package was found.
+# The first argument specifies the name (XXX) of the package.
+# The second argument specifies the message to display.
+# The third argument lists details about the find result so that
+# if they change the message will be displayed again.
+# The macro also obeys the QUIET argument to the find_package command.
+#
+# Example:
+#
+#  IF(X11_FOUND)
+#    FIND_PACKAGE_MESSAGE(X11 "Found X11: ${X11_X11_LIB}"
+#      "[${X11_X11_LIB}][${X11_INCLUDE_DIR}]")
+#  ELSE(X11_FOUND)
+#   ...
+#  ENDIF(X11_FOUND)
+
+FUNCTION(FIND_PACKAGE_MESSAGE pkg msg details)
+  # Avoid printing a message repeatedly for the same find result.
+  IF(NOT ${pkg}_FIND_QUIETLY)
+    SET(DETAILS_VAR FIND_PACKAGE_MESSAGE_DETAILS_${pkg})
+    IF(NOT "${details}" STREQUAL "${${DETAILS_VAR}}")
+      # The message has not yet been printed.
+      MESSAGE(STATUS "${msg}")
+
+      # Save the find details in the cache to avoid printing the same
+      # message again.
+      SET("${DETAILS_VAR}" "${details}"
+        CACHE INTERNAL "Details about finding ${pkg}")
+    ENDIF(NOT "${details}" STREQUAL "${${DETAILS_VAR}}")
+  ENDIF(NOT ${pkg}_FIND_QUIETLY)
+ENDFUNCTION(FIND_PACKAGE_MESSAGE)

Modules/FindQt4.cmake

@@ -1232,9 +1232,9 @@ IF (QT4_QMAKE_FOUND)
   # if the includes,libraries,moc,uic and rcc are found then we have it
   IF( QT_LIBRARY_DIR AND QT_INCLUDE_DIR AND QT_MOC_EXECUTABLE AND QT_UIC_EXECUTABLE AND QT_RCC_EXECUTABLE)
     SET( QT4_FOUND "YES" )
-    IF( NOT Qt4_FIND_QUIETLY)
-      MESSAGE(STATUS "Found Qt-Version ${QTVERSION}")
-    ENDIF( NOT Qt4_FIND_QUIETLY)
+    INCLUDE(FindPackageMessage)
+    FIND_PACKAGE_MESSAGE(Qt4 "Found Qt-Version ${QTVERSION}"
+      "[${QT_LIBRARY_DIR}][${QT_INCLUDE_DIR}][${QT_MOC_EXECUTABLE}][${QT_UIC_EXECUTABLE}][${QT_RCC_EXECUTABLE}]")
   ELSE( QT_LIBRARY_DIR AND QT_INCLUDE_DIR AND QT_MOC_EXECUTABLE AND QT_UIC_EXECUTABLE AND QT_RCC_EXECUTABLE)
     SET( QT4_FOUND "NO")
     SET(QT_QMAKE_EXECUTABLE "${QT_QMAKE_EXECUTABLE}-NOTFOUND" CACHE FILEPATH "Invalid qmake found" FORCE)

Modules/FindX11.cmake

@@ -127,6 +127,7 @@ IF (UNIX)
     GET_FILENAME_COMPONENT(X11_LIBRARY_DIR ${X11_X11_LIB} PATH)
   ENDIF(X11_X11_LIB)
 
+  SET(X11_INCLUDE_DIR) # start with empty list
   IF(X11_X11_INCLUDE_PATH)
     SET(X11_INCLUDE_DIR ${X11_INCLUDE_DIR} ${X11_X11_INCLUDE_PATH})
   ENDIF(X11_X11_INCLUDE_PATH)
@@ -145,6 +146,7 @@ IF (UNIX)
     SET(X11_INCLUDE_DIR ${X11_INCLUDE_DIR} ${X11_Xshape_INCLUDE_PATH})
   ENDIF(X11_Xshape_INCLUDE_PATH)
 
+  SET(X11_LIBRARIES) # start with empty list
   IF(X11_X11_LIB)
     SET(X11_LIBRARIES ${X11_LIBRARIES} ${X11_X11_LIB})
   ENDIF(X11_X11_LIB)
@@ -354,7 +356,9 @@ IF (UNIX)
     # Build the final list of libraries.
     SET(X11_LIBRARIES ${X11_X_PRE_LIBS} ${X11_LIBRARIES} ${X11_X_EXTRA_LIBS})
 
-    MESSAGE(STATUS "Found X11: ${X11_X11_LIB}")
+    INCLUDE(FindPackageMessage)
+    FIND_PACKAGE_MESSAGE(X11 "Found X11: ${X11_X11_LIB}"
+      "[${X11_X11_LIB}][${X11_INCLUDE_DIR}]")
   ELSE (X11_FOUND)
     IF (X11_FIND_REQUIRED)
       MESSAGE(FATAL_ERROR "Could not find X11")