Add FindLTTngUST module to find LTTng-UST library

Also detect the library version number.  Provide results as variables
and as an imported target, LTTng::UST.
Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>

Help/manual/cmake-modules.7.rst

@@ -135,6 +135,7 @@ All Modules
    /module/FindLibLZMA
    /module/FindLibXml2
    /module/FindLibXslt
+   /module/FindLTTngUST
    /module/FindLua50
    /module/FindLua51
    /module/FindLua

Help/module/FindLTTngUST.rst

+.. cmake-module:: ../../Modules/FindLTTngUST.cmake

Help/release/dev/add-FindLTTngUST.rst

+add-FindLTTngUST
+----------------
+
+* The :module:`FindLTTngUST` module was introduced to find the LTTng-UST
+  library.

Modules/FindLTTngUST.cmake

+#.rst:
+# FindLTTngUST
+# ------------
+#
+# This module finds the `LTTng-UST <http://lttng.org/>`__ library.
+#
+# Imported target
+# ^^^^^^^^^^^^^^^
+#
+# This module defines the following :prop_tgt:`IMPORTED` target:
+#
+# ``LTTng::UST``
+#   The LTTng-UST library, if found
+#
+# Result variables
+# ^^^^^^^^^^^^^^^^
+#
+# This module sets the following
+#
+# ``LTTNGUST_FOUND``
+#   ``TRUE`` if system has LTTng-UST
+# ``LTTNGUST_INCLUDE_DIRS``
+#   The LTTng-UST include directories
+# ``LTTNGUST_LIBRARIES``
+#   The libraries needed to use LTTng-UST
+# ``LTTNGUST_VERSION_STRING``
+#   The LTTng-UST version
+# ``LTTNGUST_HAS_TRACEF``
+#   ``TRUE`` if the ``tracef()`` API is available in the system's LTTng-UST
+# ``LTTNGUST_HAS_TRACELOG``
+#   ``TRUE`` if the ``tracelog()`` API is available in the system's LTTng-UST
+
+#=============================================================================
+# Copyright 2016 Kitware, Inc.
+# Copyright 2016 Philippe Proulx <pproulx@efficios.com>
+#
+# Distributed under the OSI-approved BSD License (the "License");
+# see accompanying file Copyright.txt for details.
+#
+# This software is distributed WITHOUT ANY WARRANTY; without even the
+# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+# See the License for more information.
+#=============================================================================
+# (To distribute this file outside of CMake, substitute the full
+#  License text for the above reference.)
+
+find_path(LTTNGUST_INCLUDE_DIRS NAMES lttng/tracepoint.h)
+find_library(LTTNGUST_LIBRARIES NAMES lttng-ust)
+
+if(LTTNGUST_INCLUDE_DIRS AND LTTNGUST_LIBRARIES)
+  # find tracef() and tracelog() support
+  set(LTTNGUST_HAS_TRACEF 0)
+  set(LTTNGUST_HAS_TRACELOG 0)
+
+  if(EXISTS "${LTTNGUST_INCLUDE_DIRS}/lttng/tracef.h")
+    set(LTTNGUST_HAS_TRACEF TRUE)
+  endif()
+
+  if(EXISTS "${LTTNGUST_INCLUDE_DIRS}/lttng/tracelog.h")
+    set(LTTNGUST_HAS_TRACELOG TRUE)
+  endif()
+
+  # get version
+  set(lttngust_version_file "${LTTNGUST_INCLUDE_DIRS}/lttng/ust-version.h")
+
+  if(EXISTS "${lttngust_version_file}")
+    file(STRINGS "${lttngust_version_file}" lttngust_version_major_string
+         REGEX "^[\t ]*#define[\t ]+LTTNG_UST_MAJOR_VERSION[\t ]+[0-9]+[\t ]*$")
+    file(STRINGS "${lttngust_version_file}" lttngust_version_minor_string
+         REGEX "^[\t ]*#define[\t ]+LTTNG_UST_MINOR_VERSION[\t ]+[0-9]+[\t ]*$")
+    file(STRINGS "${lttngust_version_file}" lttngust_version_patch_string
+         REGEX "^[\t ]*#define[\t ]+LTTNG_UST_PATCHLEVEL_VERSION[\t ]+[0-9]+[\t ]*$")
+    string(REGEX REPLACE ".*([0-9]+).*" "\\1"
+           lttngust_v_major "${lttngust_version_major_string}")
+    string(REGEX REPLACE ".*([0-9]+).*" "\\1"
+           lttngust_v_minor "${lttngust_version_minor_string}")
+    string(REGEX REPLACE ".*([0-9]+).*" "\\1"
+           lttngust_v_patch "${lttngust_version_patch_string}")
+    set(LTTNGUST_VERSION_STRING
+        "${lttngust_v_major}.${lttngust_v_minor}.${lttngust_v_patch}")
+    unset(lttngust_version_major_string)
+    unset(lttngust_version_minor_string)
+    unset(lttngust_version_patch_string)
+    unset(lttngust_v_major)
+    unset(lttngust_v_minor)
+    unset(lttngust_v_patch)
+  endif()
+
+  unset(lttngust_version_file)
+
+  if(NOT TARGET LTTng::UST)
+    add_library(LTTng::UST UNKNOWN IMPORTED)
+    set_target_properties(LTTng::UST PROPERTIES
+      INTERFACE_INCLUDE_DIRECTORIES "${LTTNGUST_INCLUDE_DIRS}"
+      INTERFACE_LINK_LIBRARIES ${CMAKE_DL_LIBS}
+      IMPORTED_LINK_INTERFACE_LANGUAGES "C"
+      IMPORTED_LOCATION "${LTTNGUST_LIBRARIES}")
+  endif()
+
+  # add libdl to required libraries
+  set(LTTNGUST_LIBRARIES ${LTTNGUST_LIBRARIES} ${CMAKE_DL_LIBS})
+endif()
+
+# handle the QUIETLY and REQUIRED arguments and set LTTNGUST_FOUND to
+# TRUE if all listed variables are TRUE
+include(${CMAKE_CURRENT_LIST_DIR}/FindPackageHandleStandardArgs.cmake)
+find_package_handle_standard_args(LTTngUST FOUND_VAR LTTNGUST_FOUND
+                                  REQUIRED_VARS LTTNGUST_LIBRARIES
+                                                LTTNGUST_INCLUDE_DIRS
+                                  VERSION_VAR LTTNGUST_VERSION_STRING)
+mark_as_advanced(LTTNGUST_LIBRARIES LTTNGUST_INCLUDE_DIRS)

Tests/CMakeLists.txt

@@ -1371,6 +1371,10 @@ ${CMake_BINARY_DIR}/bin/cmake -DDIR=dev -P ${CMake_SOURCE_DIR}/Utilities/Release
     add_subdirectory(FindJsonCpp)
   endif()
 
+  if(CMake_TEST_FindLTTngUST)
+    add_subdirectory(FindLTTngUST)
+  endif()
+
   if(CMake_TEST_FindOpenSSL)
     add_subdirectory(FindOpenSSL)
   endif()

Tests/CMakeOnly/AllFindModules/CMakeLists.txt

@@ -81,7 +81,7 @@ endmacro()
 # reported.
 
 foreach(VTEST ALSA ARMADILLO BZIP2 CUPS CURL EXPAT FREETYPE GETTEXT GIT HG
-        HSPELL ICOTOOL JASPER LIBLZMA LIBXML2 LIBXSLT PERL PKG_CONFIG
+        HSPELL ICOTOOL JASPER LIBLZMA LIBXML2 LIBXSLT LTTNGUST PERL PKG_CONFIG
         PostgreSQL TIFF ZLIB)
     check_version_string(${VTEST} ${VTEST}_VERSION_STRING)
 endforeach()

Tests/FindLTTngUST/CMakeLists.txt

+add_test(NAME FindLTTngUST.Test COMMAND
+  ${CMAKE_CTEST_COMMAND} -C $<CONFIGURATION>
+  --build-and-test
+  "${CMake_SOURCE_DIR}/Tests/FindLTTngUST/Test"
+  "${CMake_BINARY_DIR}/Tests/FindLTTngUST/Test"
+  ${build_generator_args}
+  --build-project TestFindLTTngUST
+  --build-options ${build_options}
+  --test-command ${CMAKE_CTEST_COMMAND} -V -C $<CONFIGURATION>
+  )

Tests/FindLTTngUST/Test/CMakeLists.txt

+cmake_minimum_required(VERSION 3.5)
+project(TestFindLTTngUST C)
+include(CTest)
+
+find_package(LTTngUST REQUIRED)
+
+add_definitions(-DCMAKE_EXPECTED_LTTNGUST_VERSION="${LTTNGUST_VERSION_STRING}")
+add_definitions(-DCMAKE_LTTNGUST_HAS_TRACEF="${LTTNGUST_HAS_TRACEF}")
+add_definitions(-DCMAKE_LTTNGUST_HAS_TRACELOG="${LTTNGUST_HAS_TRACELOG}")
+
+add_executable(test_tgt main.c)
+target_link_libraries(test_tgt LTTng::UST)
+add_test(NAME test_tgt COMMAND test_tgt)
+
+add_executable(test_var main.c)
+target_include_directories(test_var PRIVATE ${LTTNGUST_INCLUDE_DIRS})
+target_link_libraries(test_var PRIVATE ${LTTNGUST_LIBRARIES})
+add_test(NAME test_var COMMAND test_var)

Tests/FindLTTngUST/Test/main.c

+#include <assert.h>
+#include <string.h>
+#include <stdio.h>
+#include <lttng/ust-version.h>
+
+#ifdef CMAKE_LTTNGUST_HAS_TRACEF
+#include <lttng/tracef.h>
+#endif
+
+#ifdef CMAKE_LTTNGUST_HAS_TRACELOG
+#include <lttng/tracelog.h>
+#endif
+
+int main(void)
+{
+  char lttng_version_string[16];
+
+  snprintf(lttng_version_string, 16, "%u.%u.%u", LTTNG_UST_MAJOR_VERSION,
+           LTTNG_UST_MINOR_VERSION, LTTNG_UST_PATCHLEVEL_VERSION);
+  assert(!strcmp(lttng_version_string, CMAKE_EXPECTED_LTTNGUST_VERSION));
+
+#ifdef CMAKE_LTTNGUST_HAS_TRACEF
+  tracef("calling tracef()! %d %s", -23, CMAKE_EXPECTED_LTTNGUST_VERSION);
+#endif
+
+#ifdef CMAKE_LTTNGUST_HAS_TRACELOG
+  tracelog(TRACE_WARNING, "calling tracelog()! %d", 17);
+#endif
+
+  return 0;
+}