create FindXXX.cmake modules for added CPM packages (#112)

* create FindXXX.cmake modules for added CPM packages

* don't use list(PREPEND) as it unsupported on older CMake versions

* use CMAKE_BINARY_DIR

* ensure CPM.cmake is initialized only once

* import CPM.cmake in modules

.github/workflows/macos.yml

@@ -1,11 +1,17 @@
 name: MacOS
 
-on: [push]
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
 
 jobs:
   build:
 
-    runs-on: macOS-10.14
+    runs-on: macos-latest
     
     steps:
     - uses: actions/checkout@v1

.github/workflows/publish.yaml

@@ -0,0 +1,21 @@
+name: Publish
+
+on:
+  push:
+    tags:
+      - '*'
+
+jobs:
+  build:
+    name: Publish CPM.cmake
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+      - name: Upload CPM.cmake to release
+        uses: svenstaro/upload-release-action@v1-release
+        with:
+          repo_token: ${{ secrets.GITHUB_TOKEN }}
+          file: cmake/CPM.cmake
+          asset_name: CPM.cmake
+          tag: ${{ github.ref }}
+          overwrite: true

.github/workflows/ubuntu.yml

@@ -1,11 +1,17 @@
 name: Ubuntu
 
-on: [push]
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+    branches:
+    - master
 
 jobs:
   build:
 
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     
     steps:
     - uses: actions/checkout@v1

.github/workflows/windows.yml

@@ -1,11 +1,17 @@
 name: Windows
 
-on: [push]
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+    branches:
+    - master
 
 jobs:
   build:
 
-    runs-on: windows-2019
+    runs-on: windows-latest
     
     steps:
     - uses: actions/checkout@v1

README.md

@@ -36,6 +36,7 @@ CPMAddPackage(
 
 The origin may be specified by a `GIT_REPOSITORY`, but other sources, such as direct URLs, are [also supported](https://cmake.org/cmake/help/v3.11/module/ExternalProject.html#external-project-definition).
 If `GIT_TAG` hasn't been explicitly specified it defaults to `v(VERSION)`, a common convention for git projects.
+On the other hand, if `VERSION` hasn't been explicitly specified, CPM can automatically identify the version from the git tag in some common cases. 
 `GIT_TAG` can also be set to a specific commit or a branch name such as `master` to always download the most recent version.
 The optional argument `FIND_PACKAGE_ARGUMENTS` can be specified to a string of parameters that will be passed to `find_package` if enabled (see below).
 
@@ -80,10 +81,10 @@ To add CPM to your current project, simply add `cmake/CPM.cmake` to your project
 
 ```bash
 mkdir -p cmake
-wget -O cmake/CPM.cmake https://raw.githubusercontent.com/TheLartians/CPM.cmake/master/cmake/CPM.cmake
+wget -O cmake/CPM.cmake https://github.com/TheLartians/CPM.cmake/releases/latest/download/CPM.cmake
 ```
 
-You can also use CMake to download CPM for you. See the [wiki](https://github.com/TheLartians/CPM/wiki/Adding-CPM) for more details.
+You can also use CMake to download CPM for you. See the [wiki](https://github.com/TheLartians/CPM.cmake/wiki/Downloading-CPM.cmake-in-CMake) for more details.
 
 ## Updating CPM
 

cmake/CPM.cmake

@@ -28,7 +28,7 @@
 
 cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
 
-set(CURRENT_CPM_VERSION 0.16)
+set(CURRENT_CPM_VERSION 0.21)
 
 if(CPM_DIRECTORY)
   if(NOT ${CPM_DIRECTORY} MATCHES ${CMAKE_CURRENT_LIST_DIR})
@@ -41,14 +41,23 @@ See https://github.com/TheLartians/CPM.cmake for more information."
     endif()
     return()
   endif()
+
+  get_property(CPM_INITIALIZED GLOBAL "" PROPERTY CPM_INITIALIZED SET)   
+  if (CPM_INITIALIZED)
+    return()
+  endif()
 endif()
 
+set_property(GLOBAL PROPERTY CPM_INITIALIZED true) 
+
 option(CPM_USE_LOCAL_PACKAGES "Always try to use `find_package` to get dependencies" $ENV{CPM_USE_LOCAL_PACKAGES})
 option(CPM_LOCAL_PACKAGES_ONLY "Only use `find_package` to get dependencies" $ENV{CPM_LOCAL_PACKAGES_ONLY})
 option(CPM_DOWNLOAD_ALL "Always download dependencies from source" $ENV{CPM_DOWNLOAD_ALL})
+option(CPM_DONT_UPDATE_MODULE_PATH "Don't update the module path to allow using find_package" $ENV{CPM_DONT_UPDATE_MODULE_PATH})
 
 set(CPM_VERSION ${CURRENT_CPM_VERSION} CACHE INTERNAL "")
 set(CPM_DIRECTORY ${CMAKE_CURRENT_LIST_DIR} CACHE INTERNAL "")
+set(CPM_FILE ${CMAKE_CURRENT_LIST_FILE} CACHE INTERNAL "")
 set(CPM_PACKAGES "" CACHE INTERNAL "")
 set(CPM_DRY_RUN OFF CACHE INTERNAL "Don't download or configure dependencies (for testing)")
 
@@ -60,6 +69,15 @@ endif()
 
 set(CPM_SOURCE_CACHE ${CPM_SOURCE_CACHE_DEFAULT} CACHE PATH "Directory to downlaod CPM dependencies")
 
+if (NOT CPM_DONT_UPDATE_MODULE_PATH)
+  set(CPM_MODULE_PATH "${CMAKE_BINARY_DIR}/CPM_modules" CACHE INTERNAL "")
+  # remove old modules
+  FILE(REMOVE_RECURSE ${CPM_MODULE_PATH})
+  file(MAKE_DIRECTORY ${CPM_MODULE_PATH})
+  # locally added CPM modules should override global packages
+  set(CMAKE_MODULE_PATH "${CPM_MODULE_PATH};${CMAKE_MODULE_PATH}")
+endif()
+
 include(FetchContent)
 include(CMakeParseArguments)
 
@@ -70,7 +88,7 @@ endif()
 
 function(cpm_find_package NAME VERSION)
   string(REPLACE " " ";" EXTRA_ARGS "${ARGN}")
-  find_package(${NAME} ${VERSION} ${EXTRA_ARGS})
+  find_package(${NAME} ${VERSION} ${EXTRA_ARGS} QUIET)
   if(${CPM_ARGS_NAME}_FOUND)
     message(STATUS "${CPM_INDENT} using local package ${CPM_ARGS_NAME}@${${CPM_ARGS_NAME}_VERSION}")
     CPMRegisterPackage(${CPM_ARGS_NAME} "${${CPM_ARGS_NAME}_VERSION}")
@@ -80,6 +98,15 @@ function(cpm_find_package NAME VERSION)
   endif()
 endfunction()
 
+# Create a custom FindXXX.cmake module for a CPM package
+# This prevents `find_package(NAME)` from finding the system library
+function(CPMCreateModuleFile Name)
+  if (NOT CPM_DONT_UPDATE_MODULE_PATH)
+    # erase any previous modules
+    FILE(WRITE ${CPM_MODULE_PATH}/Find${Name}.cmake "include(${CPM_FILE})\n${ARGN}\nset(${Name}_FOUND TRUE)")
+  endif()
+endfunction()
+
 # Find a package locally or fallback to CPMAddPackage
 function(CPMFindPackage)
   set(oneValueArgs
@@ -124,7 +151,7 @@ function(CPMAddPackage)
     OPTIONS
   )
 
-  cmake_parse_arguments(CPM_ARGS "" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+  cmake_parse_arguments(CPM_ARGS "" "${oneValueArgs}" "${multiValueArgs}" "${ARGN}")
 
   if(CPM_USE_LOCAL_PACKAGES OR CPM_LOCAL_PACKAGES_ONLY)
     cpm_find_package(${CPM_ARGS_NAME} "${CPM_ARGS_VERSION}" ${CPM_ARGS_FIND_PACKAGE_ARGUMENTS})
@@ -167,7 +194,7 @@ function(CPMAddPackage)
     list(APPEND CPM_ARGS_UNPARSED_ARGUMENTS GIT_REPOSITORY "https://gitlab.com/${CPM_ARGS_GITLAB_REPOSITORY}.git")
   endif()
 
-  if (${CPM_ARGS_NAME} IN_LIST CPM_PACKAGES)
+  if ("${CPM_ARGS_NAME}" IN_LIST CPM_PACKAGES)
     CPMGetPackageVersion(${CPM_ARGS_NAME} CPM_PACKAGE_VERSION)
     if(${CPM_PACKAGE_VERSION} VERSION_LESS ${CPM_ARGS_VERSION})
       message(WARNING "${CPM_INDENT} requires a newer version of ${CPM_ARGS_NAME} (${CPM_ARGS_VERSION}) than currently included (${CPM_PACKAGE_VERSION}).")
@@ -208,28 +235,30 @@ function(CPMAddPackage)
 
   if (DEFINED CPM_ARGS_DOWNLOAD_COMMAND)
     set(FETCH_CONTENT_DECLARE_EXTRA_OPTS DOWNLOAD_COMMAND ${CPM_ARGS_DOWNLOAD_COMMAND})
-  else()
-    if (CPM_SOURCE_CACHE AND NOT DEFINED CPM_ARGS_SOURCE_DIR)
-      string(TOLOWER ${CPM_ARGS_NAME} lower_case_name)
-      set(origin_parameters ${CPM_ARGS_UNPARSED_ARGUMENTS})
-      list(SORT origin_parameters)
-      string(SHA1 origin_hash "${origin_parameters}")
-      set(download_directory ${CPM_SOURCE_CACHE}/${lower_case_name}/${origin_hash})
-      list(APPEND FETCH_CONTENT_DECLARE_EXTRA_OPTS SOURCE_DIR ${download_directory})
-      if (EXISTS ${download_directory})
-        list(APPEND FETCH_CONTENT_DECLARE_EXTRA_OPTS DOWNLOAD_COMMAND ":")
-        set(PACKAGE_INFO "${download_directory}")
-      else()
-        # remove timestamps so CMake will re-download the dependency
-        file(REMOVE_RECURSE ${CMAKE_BINARY_DIR}/_deps/${lower_case_name}-subbuild)
-        set(PACKAGE_INFO "${PACKAGE_INFO} -> ${download_directory}")
-      endif()
+  elseif(DEFINED CPM_ARGS_SOURCE_DIR)
+    set(FETCH_CONTENT_DECLARE_EXTRA_OPTS SOURCE_DIR ${CPM_ARGS_SOURCE_DIR})
+  elseif (CPM_SOURCE_CACHE)
+    string(TOLOWER ${CPM_ARGS_NAME} lower_case_name)
+    set(origin_parameters ${CPM_ARGS_UNPARSED_ARGUMENTS})
+    list(SORT origin_parameters)
+    string(SHA1 origin_hash "${origin_parameters}")
+    set(download_directory ${CPM_SOURCE_CACHE}/${lower_case_name}/${origin_hash})
+    list(APPEND FETCH_CONTENT_DECLARE_EXTRA_OPTS SOURCE_DIR ${download_directory})
+    if (EXISTS ${download_directory})
+      # disable the download command to allow offline builds
+      list(APPEND FETCH_CONTENT_DECLARE_EXTRA_OPTS DOWNLOAD_COMMAND "${CMAKE_COMMAND}")
+      set(PACKAGE_INFO "${download_directory}")
+    else()
+      # remove timestamps so CMake will re-download the dependency
+      file(REMOVE_RECURSE ${CMAKE_BINARY_DIR}/_deps/${lower_case_name}-subbuild)
+      set(PACKAGE_INFO "${PACKAGE_INFO} -> ${download_directory}")
     endif()
   endif()
 
   cpm_declare_fetch(${CPM_ARGS_NAME} ${CPM_ARGS_VERSION} ${PACKAGE_INFO} "${CPM_ARGS_UNPARSED_ARGUMENTS}" ${FETCH_CONTENT_DECLARE_EXTRA_OPTS})
   cpm_fetch_package(${CPM_ARGS_NAME} ${DOWNLOAD_ONLY})
   cpm_get_fetch_properties(${CPM_ARGS_NAME})
+  CPMCreateModuleFile(${CPM_ARGS_NAME} "CPMAddPackage(${ARGN})")
   SET(${CPM_ARGS_NAME}_ADDED YES)
   cpm_export_variables()
 endfunction()

cmake/testing.cmake

@@ -20,3 +20,15 @@ endfunction()
 function(ASSERTION_FAILED)
   message(FATAL_ERROR "assertion failed: ${ARGN}")
 endfunction()
+
+function(ASSERT_EXISTS file)
+  if (NOT EXISTS ${file}) 
+    message(FATAL_ERROR "assertion failed: file ${file} does not exist")
+  endif()
+endfunction()
+
+function(ASSERT_NOT_EXISTS file)
+  if (EXISTS ${file}) 
+    message(FATAL_ERROR "assertion failed: file ${file} exists")
+  endif()
+endfunction()

examples/catch2/CMakeLists.txt

@@ -2,10 +2,6 @@ cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
 
 project(CPMExampleCatch2)
 
-# ---- Options ----
-
-option(ENABLE_TEST_COVERAGE "Enable test coverage" OFF)
-
 # ---- Dependencies ----
 
 include(../../cmake/CPM.cmake)
@@ -26,16 +22,9 @@ CPMAddPackage(
 
 add_executable(CPMExampleCatch2 main.cpp)
 target_link_libraries(CPMExampleCatch2 fibonacci Catch2)
-set_target_properties(CPMExampleCatch2 PROPERTIES CXX_STANDARD 17 COMPILE_FLAGS "-Wall -pedantic -Wextra -Werror")
+set_target_properties(CPMExampleCatch2 PROPERTIES CXX_STANDARD 17)
 
 # ---- Enable testing ----
 
 ENABLE_TESTING() 
 ADD_TEST(CPMExampleCatch2 CPMExampleCatch2)
-
-# ---- Add code coverage ----
-
-if (${ENABLE_TEST_COVERAGE})
-  set_target_properties(CPMExampleCatch2 PROPERTIES CXX_STANDARD 17 COMPILE_FLAGS "-O0 -g -fprofile-arcs -ftest-coverage --coverage")
-  target_link_options(CPMExampleCatch2 PUBLIC "--coverage")
-endif()

examples/cxxopts/CMakeLists.txt

@@ -2,10 +2,6 @@ cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
 
 project(CPMExampleCXXOpts)
 
-# ---- Options ----
-
-option(ENABLE_TEST_COVERAGE "Enable test coverage" OFF)
-
 # ---- Dependencies ----
 
 include(../../cmake/CPM.cmake)
@@ -23,4 +19,4 @@ CPMAddPackage(
 
 add_executable(CPMExampleCXXOpts main.cpp)
 target_link_libraries(CPMExampleCXXOpts cxxopts)
-set_target_properties(CPMExampleCXXOpts PROPERTIES CXX_STANDARD 17 COMPILE_FLAGS "-Wall -pedantic -Wextra -Werror")
+set_target_properties(CPMExampleCXXOpts PROPERTIES CXX_STANDARD 17)

examples/doctest/CMakeLists.txt

@@ -2,10 +2,6 @@ cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
 
 project(CPMExampleDoctest)
 
-# ---- Options ----
-
-option(ENABLE_TEST_COVERAGE "Enable test coverage" OFF)
-
 # ---- Dependencies ----
 
 include(../../cmake/CPM.cmake)
@@ -26,16 +22,9 @@ CPMAddPackage(
 
 add_executable(CPMExampleDoctest main.cpp)
 target_link_libraries(CPMExampleDoctest fibonacci doctest)
-set_target_properties(CPMExampleDoctest PROPERTIES CXX_STANDARD 17 COMPILE_FLAGS "-Wall -pedantic -Wextra -Werror")
+set_target_properties(CPMExampleDoctest PROPERTIES CXX_STANDARD 17)
 
 # ---- Enable testing ----
 
 ENABLE_TESTING() 
 ADD_TEST(CPMExampleDoctest CPMExampleDoctest)
-
-# ---- Add code coverage ----
-
-if (${ENABLE_TEST_COVERAGE})
-  set_target_properties(CPMExampleDoctest PROPERTIES CXX_STANDARD 17 COMPILE_FLAGS "-O0 -g -fprofile-arcs -ftest-coverage --coverage")
-  target_link_options(CPMExampleDoctest PUBLIC "--coverage")
-endif()

examples/fmt/CMakeLists.txt

@@ -0,0 +1,19 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMJSONExample)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME fmt
+  GIT_TAG 6.1.2
+  GITHUB_REPOSITORY fmtlib/fmt
+)
+
+# ---- Executable ----
+
+add_executable(CPMFmtExample "main.cpp")
+set_target_properties(CPMFmtExample PROPERTIES CXX_STANDARD 17)        
+target_link_libraries(CPMFmtExample fmt)

examples/fmt/main.cpp

@@ -0,0 +1,6 @@
+#include <fmt/format.h>
+
+int main(){
+  fmt::print("Hello, {}!\n", "world");
+  return 0;
+}

examples/gtest/CMakeLists.txt

@@ -2,10 +2,6 @@ cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
 
 project(CPMExampleGtest)
 
-# ---- Options ----
-
-option(ENABLE_TEST_COVERAGE "Enable test coverage" OFF)
-
 # ---- Dependencies ----
 
 include(../../cmake/CPM.cmake)
@@ -36,10 +32,3 @@ set_target_properties(CPMExampleGtest PROPERTIES CXX_STANDARD 17)
 
 enable_testing() 
 add_test(CPMExampleGtest CPMExampleGtest)
-
-# ---- Add code coverage ----
-
-if (${ENABLE_TEST_COVERAGE})
-  set_target_properties(CPMExampleGtest PROPERTIES CXX_STANDARD 17 COMPILE_FLAGS "-O0 -g -fprofile-arcs -ftest-coverage --coverage")
-  target_link_options(CPMExampleGtest PUBLIC "--coverage")
-endif()

test/unit/cache.cmake

@@ -8,6 +8,7 @@ set(CPM_SOURCE_CACHE_DIR "${CMAKE_CURRENT_BINARY_DIR}/CPM")
 set(TEST_BUILD_DIR ${CMAKE_CURRENT_BINARY_DIR}/cache)
 
 function(clear_cache)
+  message(STATUS "clearing CPM cache")
   FILE(REMOVE_RECURSE ${CPM_SOURCE_CACHE_DIR})
   
   if (EXISTS "${CPM_SOURCE_CACHE_DIR}")
@@ -104,6 +105,16 @@ if (NOT EXISTS "${CPM_SOURCE_CACHE_DIR}/fibonacci")
   ASSERTION_FAILED("fibonacci not in cache")
 endif()
 
+## Reuse cached packages for other build
+
+execute_process(
+  COMMAND 
+  ${CMAKE_COMMAND} -E env "CPM_SOURCE_CACHE=${CPM_SOURCE_CACHE_DIR}" ${CMAKE_COMMAND} "-H${CMAKE_CURRENT_LIST_DIR}/cache" "-B${TEST_BUILD_DIR}-2"
+  RESULT_VARIABLE ret
+)
+
+ASSERT_EQUAL(${ret} "0")
+
 ## Overwrite CPM_SOURCE_CACHE with argument
 
 reset_test()

test/unit/modules.cmake

@@ -0,0 +1,30 @@
+
+include(CMakePackageConfigHelpers)
+include(${CPM_PATH}/testing.cmake)
+
+set(TEST_BUILD_DIR ${CMAKE_CURRENT_BINARY_DIR}/modules)
+
+function(initProjectWithDependency TEST_DEPENDENCY_NAME)
+  configure_package_config_file(
+    "${CMAKE_CURRENT_LIST_DIR}/test_project/CMakeLists.txt.in"
+    "${CMAKE_CURRENT_LIST_DIR}/test_project/CMakeLists.txt"
+    INSTALL_DESTINATION ${CMAKE_CURRENT_BINARY_DIR}/junk
+  )
+
+  execute_process(
+    COMMAND 
+    ${CMAKE_COMMAND} "-H${CMAKE_CURRENT_LIST_DIR}/test_project" "-B${TEST_BUILD_DIR}"
+    RESULT_VARIABLE ret
+  )
+
+  ASSERT_EQUAL(${ret} "0")
+endfunction()
+
+initProjectWithDependency(A)
+ASSERT_EXISTS(${TEST_BUILD_DIR}/CPM_modules)
+ASSERT_EXISTS(${TEST_BUILD_DIR}/CPM_modules/FindA.cmake)
+ASSERT_NOT_EXISTS(${TEST_BUILD_DIR}/CPM_modules/FindB.cmake)
+
+initProjectWithDependency(B)
+ASSERT_NOT_EXISTS(${TEST_BUILD_DIR}/CPM_modules/FindA.cmake)
+ASSERT_EXISTS(${TEST_BUILD_DIR}/CPM_modules/FindB.cmake)

test/unit/source_dir.cmake

@@ -0,0 +1,21 @@
+
+include(CMakePackageConfigHelpers)
+include(${CPM_PATH}/testing.cmake)
+
+set(TEST_BUILD_DIR ${CMAKE_CURRENT_BINARY_DIR}/source_dir)
+
+set(TEST_DEPENDENCY_NAME Dependency)
+
+configure_package_config_file(
+  "${CMAKE_CURRENT_LIST_DIR}/test_project/CMakeLists.txt.in"
+  "${CMAKE_CURRENT_LIST_DIR}/test_project/CMakeLists.txt"
+  INSTALL_DESTINATION ${CMAKE_CURRENT_BINARY_DIR}/junk
+)
+
+execute_process(
+  COMMAND 
+  ${CMAKE_COMMAND} "-H${CMAKE_CURRENT_LIST_DIR}/test_project" "-B${TEST_BUILD_DIR}"
+  RESULT_VARIABLE ret
+)
+
+ASSERT_EQUAL(${ret} "0")

test/unit/test_project/.gitignore

@@ -0,0 +1 @@
+/CMakeLists.txt

test/unit/test_project/CMakeLists.txt.in

@@ -0,0 +1,26 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMExampleCatch2)
+
+# ---- Options ----
+
+option(ENABLE_TEST_COVERAGE "Enable test coverage" OFF)
+
+# ---- Dependencies ----
+
+include(@CPM_PATH@/CPM.cmake)
+
+CPMAddPackage(
+  NAME @TEST_DEPENDENCY_NAME@
+  SOURCE_DIR ${CMAKE_CURRENT_LIST_DIR}/dependency
+)
+
+# ---- check if generated modules override find_package ----
+
+if (@test_check_find_package@)
+  find_package(@TEST_DEPENDENCY_NAME@ REQUIRED)
+endif()
+
+# ---- Call dependency method to validate correct addition of directory ----
+
+dependency_function()

test/unit/test_project/dependency/CMakeLists.txt

@@ -0,0 +1,4 @@
+
+function(dependency_function)
+  message("called external method")
+endfunction()