Fix linking with system library (libsqlite3)

Add FindSQLite3 from CMake v3.14 in cmake subdir custom CMake modules like FindSQLiteCpp
Add this cmake subdir to CMAKE_MODULE_PATH
Add a Travis CI build configuration using the libsqlite3-dev packagee from the Linux/Ubuntu distribution

Author: SRombauts

.travis.yml

@@ -9,6 +9,13 @@ os: linux
 cache:
   apt: true
 
+env:
+  global:
+    - BUILD_TYPE=Debug
+    - ASAN=ON
+    - INTERNAL_SQLITE=ON
+    - VALGRIND=OFF
+
 matrix:
   include:
 
@@ -31,15 +38,14 @@ matrix:
     - dist: bionic
       env:
         - cc=gcc cxx=g++
-        - BUILD_TYPE=Debug
-        - ASAN=ON GCOV=ON
+        - GCOV=ON
         - COVERALLS=true
 
     # GCC Debug build with Valgrind instead of Address Sanitizer
     - dist: bionic
       env:
         - cc=gcc cxx=g++
-        - BUILD_TYPE=Debug
+        - ASAN=OFF
         - VALGRIND=true
 
     # GCC Release build
@@ -48,17 +54,19 @@ matrix:
         - cc=gcc cxx=g++
         - BUILD_TYPE=Release
 
+    # GCC test linking with libsqlite3-dev package
+    - dist: bionic
+      env:
+        - cc=gcc cxx=g++
+        - INTERNAL_SQLITE=OFF
+
     - dist: xenial
       env:
         - cc=gcc cxx=g++
-        - BUILD_TYPE=Debug
-        - ASAN=ON
 
     - dist: trusty
       env:
         - cc=gcc cxx=g++
-        - BUILD_TYPE=Debug
-        - ASAN=ON
 
     ##########################################################################
     # Clang on Linux
@@ -67,20 +75,14 @@ matrix:
     - dist: bionic
       env:
         - cc=clang cxx=clang++
-        - BUILD_TYPE=Debug
-        - ASAN=ON
 
     - dist: xenial
       env:
         - cc=clang cxx=clang++
-        - BUILD_TYPE=Debug
-        - ASAN=ON
 
     - dist: trusty
       env:
         - cc=clang cxx=clang++
-        - BUILD_TYPE=Debug
-        - ASAN=ON
 
     ##########################################################################
     # Clang on OSX
@@ -90,23 +92,20 @@ matrix:
     - os: osx
       env:
         - cc=clang cxx=clang++
-        - BUILD_TYPE=Debug
-        - ASAN=ON
 
     # XCode 8.3
     - os: osx
       osx_image: xcode8.3
       env:
         - cc=clang cxx=clang++
-        - BUILD_TYPE=Debug
-        - ASAN=ON
 
 before_install:
   # Coverity: don't use addons.coverity_scan since it run on every job of the build matrix, which waste resources and exhausts quotas
   # Note: the job dedicated to Coverity need to only run the shell script and then exit (to not try to build and run unit tests etc.)
   - if [[ -n "$COVERITY_SCAN_PROJECT_NAME" ]] ; then curl -s https://scan.coverity.com/scripts/travisci_build_coverity_scan.sh | bash ; exit 0 ; fi
 
-  - if [[ "$VALGRIND" == "true" ]]; then sudo apt-get install -qq valgrind ; fi
+  - if [[ "$INTERNAL_SQLITE" == "OFF" ]]; then sudo apt-get install libsqlite3-dev ; fi
+  - if [[ "$VALGRIND" == "true" ]]; then sudo apt-get install valgrind ; fi
   - if [[ "$COVERALLS" == "true" ]]; then pip install --user cpp-coveralls ; fi
 
     # Set the compiler environment variables properly
@@ -117,7 +116,7 @@ before_install:
 before_script:
   - mkdir build
   - cd build
-  - cmake -DCMAKE_VERBOSE_MAKEFILE=ON -DCMAKE_BUILD_TYPE=$BUILD_TYPE -DSQLITECPP_USE_ASAN=$ASAN -DSQLITECPP_USE_GCOV=$GCOV -DSQLITECPP_BUILD_EXAMPLES=ON -DSQLITECPP_BUILD_TESTS=ON ..
+  - cmake -DCMAKE_VERBOSE_MAKEFILE=ON -DCMAKE_BUILD_TYPE=$BUILD_TYPE -DSQLITECPP_INTERNAL_SQLITE=$INTERNAL_SQLITE -DSQLITECPP_USE_ASAN=$ASAN -DSQLITECPP_USE_GCOV=$GCOV -DSQLITECPP_BUILD_EXAMPLES=ON -DSQLITECPP_BUILD_TESTS=ON ..
 
 # build examples, and run tests (ie make & make test)
 script:

CMakeLists.txt

@@ -5,6 +5,7 @@
 # Distributed under the MIT License (MIT) (See accompanying file LICENSE.txt
 # or copy at http://opensource.org/licenses/MIT)
 cmake_minimum_required(VERSION 3.1) # for "CMAKE_CXX_STANDARD" version
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake") # custom CMake modules like FindSQLiteCpp
 project(SQLiteCpp VERSION "2.99")
 
 # SQLiteC++ 3.x now requires C++11 compiler
@@ -154,6 +155,8 @@ set(SQLITECPP_SCRIPT
  cpplint.py
  Doxyfile
  cmake/FindSQLiteCpp.cmake
+ cmake/FindSQLite3.cmake
+ cmake/SQLiteCppConfig.cmake.in
 )
 source_group(scripts FILES ${SQLITECPP_SCRIPT})
 
@@ -246,15 +249,17 @@ install(FILES
 
 option(SQLITECPP_INTERNAL_SQLITE "Add the internal SQLite3 source to the project." ON)
 if (SQLITECPP_INTERNAL_SQLITE)
+    message(STATUS "Compile sqlite3 from source in subdirectory")
     # build the SQLite3 C library (for ease of use/compatibility) versus Linux sqlite3-dev package
     add_subdirectory(sqlite3)
     target_include_directories(sqlite3 PUBLIC "${PROJECT_SOURCE_DIR}/sqlite3")
     target_include_directories(SQLiteCpp PRIVATE "${PROJECT_SOURCE_DIR}/sqlite3")
 else (SQLITECPP_INTERNAL_SQLITE)
     find_package (SQLite3 REQUIRED)
     if (SQLITE3_FOUND)
+        message(STATUS "Link to sqlite3 system library")
         include_directories(${SQLITE3_INCLUDE_DIRS})
-        target_link_libraries (SQLiteCpp ${SQLITE3_LIBRARIES})
+        target_link_libraries(SQLiteCpp ${SQLITE3_LIBRARIES})
     endif (SQLITE3_FOUND)
 endif (SQLITECPP_INTERNAL_SQLITE)
 
@@ -336,7 +341,7 @@ if (SQLITECPP_BUILD_TESTS)
     else (GTEST_FOUND)
         # deactivate some warnings for compiling the googletest library
         if (NOT MSVC)
-            add_compile_options(-Wno-variadic-macros -Wno-long-long -Wno-switch-enum -Wno-float-equal -Wno-conversion-null -Wno-switch-default -Wno-pedantic)
+            add_compile_options(-Wno-switch-enum)
         endif (NOT MSVC)
 
         # add the subdirectory containing the CMakeLists.txt for the googletest library

cmake/FindSQLite3.cmake

@@ -0,0 +1,66 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+#[=======================================================================[.rst:
+FindSQLite3
+-----------
+
+Find the SQLite libraries, v3
+
+IMPORTED targets
+^^^^^^^^^^^^^^^^
+
+This module defines the following :prop_tgt:`IMPORTED` target:
+
+``SQLite::SQLite3``
+
+Result variables
+^^^^^^^^^^^^^^^^
+
+This module will set the following variables if found:
+
+``SQLite3_INCLUDE_DIRS``
+  where to find sqlite3.h, etc.
+``SQLite3_LIBRARIES``
+  the libraries to link against to use SQLite3.
+``SQLite3_VERSION``
+  version of the SQLite3 library found
+``SQLite3_FOUND``
+  TRUE if found
+
+#]=======================================================================]
+
+# Look for the necessary header
+find_path(SQLite3_INCLUDE_DIR NAMES sqlite3.h)
+mark_as_advanced(SQLite3_INCLUDE_DIR)
+
+# Look for the necessary library
+find_library(SQLite3_LIBRARY NAMES sqlite3 sqlite)
+mark_as_advanced(SQLite3_LIBRARY)
+
+# Extract version information from the header file
+if(SQLite3_INCLUDE_DIR)
+    file(STRINGS ${SQLite3_INCLUDE_DIR}/sqlite3.h _ver_line
+         REGEX "^#define SQLITE_VERSION  *\"[0-9]+\\.[0-9]+\\.[0-9]+\""
+         LIMIT_COUNT 1)
+    string(REGEX MATCH "[0-9]+\\.[0-9]+\\.[0-9]+"
+           SQLite3_VERSION "${_ver_line}")
+    unset(_ver_line)
+endif()
+
+include(${CMAKE_ROOT}/Modules/FindPackageHandleStandardArgs.cmake)
+find_package_handle_standard_args(SQLite3
+    REQUIRED_VARS SQLite3_INCLUDE_DIR SQLite3_LIBRARY
+    VERSION_VAR SQLite3_VERSION)
+
+# Create the imported target
+if(SQLite3_FOUND)
+    set(SQLite3_INCLUDE_DIRS ${SQLite3_INCLUDE_DIR})
+    set(SQLite3_LIBRARIES ${SQLite3_LIBRARY})
+    if(NOT TARGET SQLite::SQLite3)
+        add_library(SQLite::SQLite3 UNKNOWN IMPORTED)
+        set_target_properties(SQLite::SQLite3 PROPERTIES
+            IMPORTED_LOCATION             "${SQLite3_LIBRARY}"
+            INTERFACE_INCLUDE_DIRECTORIES "${SQLite3_INCLUDE_DIR}")
+    endif()
+endif()