Single-argument shorthand syntax for CPMAddPackage (#207)

* Added quotes in equality checks so lists can be compared

* Function to parse argument of CPMAddPackage in case a single one was provided

* Error on URL type in CPMAddPackage single-arg

* Fixed format

* Support single argument syntax of CPMAddPackage

* Documenting and showcasing the new shorthand syntax of CPMAddPackage

* Auto EXCLUDE_FROM_ALL for the shorthand syntax

* Fixed accidental paste of TOLOWER

* Document why some test cases are commented out

Co-authored-by: Lars Melchior <TheLartians@users.noreply.github.com>

* Update README.md

Co-authored-by: Lars Melchior <TheLartians@users.noreply.github.com>

* Removed GitHub as the default package shorthand provider

Co-authored-by: Lars Melchior <TheLartians@users.noreply.github.com>

Author: iboB

README.md

@@ -47,6 +47,19 @@ On the other hand, if `VERSION` hasn't been explicitly specified, CPM can automa
 `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).
 
+A single-argument compact syntax is also supported:
+
+```cmake
+# A git package from a given uri with a version
+CPMAddPackage("uri@version")
+# A git package from a given uri with a git tag or commit hash, or branch name
+CPMAddPackage("uri#tag")
+# A git package with both version and tag provided
+CPMAddPackage("uri@version#tag")
+```
+
+In the shorthand syntax if the URI is of the form `gh:user/name`, it is interpreted as GitHub URI and converted to `https://github.com/user/name.git`. If the URI is of the form `gl:user/name`, it is interpreted as a [GitLab](https://gitlab.com/explore/) URI and coverted to `https://gitlab.com/user/name.git`. Otherwise the URI used verbatim as a git URL.
+
 After calling `CPMAddPackage` or `CPMFindPackage`, the following variables are defined in the local scope, where `<dependency>` is the name of the dependency.
 
 - `<dependency>_SOURCE_DIR` is the path to the source of the dependency.
@@ -70,10 +83,7 @@ add_executable(tests tests.cpp)
 # add dependencies
 include(cmake/CPM.cmake)
 
-CPMAddPackage(
-  GITHUB_REPOSITORY catchorg/Catch2
-  VERSION 2.5.0
-)
+CPMAddPackage(gh:catchorg/Catch2@2.5.0)
 
 # link dependencies
 target_link_libraries(tests Catch2)
@@ -244,21 +254,13 @@ See the [wiki](https://github.com/cpm-cmake/CPM.cmake/wiki/More-Snippets) for mo
 ### [Catch2](https://github.com/catchorg/Catch2)
 
 ```cmake
-CPMAddPackage(
-  NAME Catch2
-  GITHUB_REPOSITORY catchorg/Catch2
-  VERSION 2.5.0
-)
+CPMAddPackage(gh:catchorg/Catch2@2.5.0)
 ```
 
 ### [Boost (via boost-cmake)](https://github.com/Orphis/boost-cmake)
 
 ```CMake
-CPMAddPackage(
-  NAME boost-cmake
-  GITHUB_REPOSITORY Orphis/boost-cmake
-  VERSION 1.67.0
-)
+CPMAddPackage(gh:Orphis/boost-cmake@1.67.0)
 ```
 
 ### [cxxopts](https://github.com/jarro2783/cxxopts)

cmake/CPM.cmake

@@ -252,8 +252,85 @@ function(cpm_check_if_package_already_added CPM_ARGS_NAME CPM_ARGS_VERSION CPM_A
   endif()
 endfunction()
 
+# Parse the argument of CPMAddPackage in case a single one was provided and convert it to a list of
+# arguments which can then be parsed idiomatically. For example gh:foo/bar@1.2.3 will be converted
+# to: GITHUB_REPOSITORY;foo/bar;VERSION;1.2.3
+function(cpm_parse_add_package_single_arg arg outArgs)
+  # Look for a scheme
+  if("${arg}" MATCHES "^([a-zA-Z]+):(.+)$")
+    string(TOLOWER "${CMAKE_MATCH_1}" scheme)
+    set(uri "${CMAKE_MATCH_2}")
+
+    # Check for CPM-specific schemes
+    if(scheme STREQUAL "gh")
+      set(out "GITHUB_REPOSITORY;${uri}")
+      set(packageType "git")
+    elseif(scheme STREQUAL "gl")
+      set(out "GITLAB_REPOSITORY;${uri}")
+      set(packageType "git")
+      # A CPM-specific scheme was not found. Looks like this is a generic URL so try to determine
+      # type
+    elseif(arg MATCHES ".git/?(@|#|$)")
+      set(out "GIT_REPOSITORY;${arg}")
+      set(packageType "git")
+    else()
+      # This error here is temporary. We can't provide URLs from here until we support inferring the
+      # package name from an url. When this is supported, remove this error as well as commented out
+      # tests in test/unit/parse_add_package_single_arg.cmake
+      message(FATAL_ERROR "CPM: Unsupported package type of '${arg}'")
+
+      # Fall back to a URL
+      set(out "URL;${arg}")
+      set(packageType "archive")
+
+      # We could also check for SVN since FetchContent supports it, but SVN is so rare these days.
+      # We just won't bother with the additional complexity it will induce in this function. SVN is
+      # done by multi-arg
+    endif()
+  else()
+    if(arg MATCHES ".git/?(@|#|$)")
+      set(out "GIT_REPOSITORY;${arg}")
+      set(packageType "git")
+    else()
+      # Give up
+      message(FATAL_ERROR "CPM: Can't determine package type of '${arg}'")
+    endif()
+  endif()
+
+  # For all packages we interpret @... as version. Only replace the last occurence. Thus URIs
+  # containing '@' can be used
+  string(REGEX REPLACE "@([^@]+)$" ";VERSION;\\1" out "${out}")
+
+  # Parse the rest according to package type
+  if(packageType STREQUAL "git")
+    # For git repos we interpret #... as a tag or branch or commit hash
+    string(REGEX REPLACE "#([^#]+)$" ";GIT_TAG;\\1" out "${out}")
+  elseif(packageType STREQUAL "archive")
+    # For archives we interpret #... as a URL hash.
+    string(REGEX REPLACE "#([^#]+)$" ";URL_HASH;\\1" out "${out}")
+    # We don't try to parse the version if it's not provided explicitly. cpm_get_version_from_url
+    # should do this at a later point
+  else()
+    # We should never get here. This is an assertion and hitting it means there's a bug in the code
+    # above. A packageType was set, but not handled by this if-else.
+    message(FATAL_ERROR "CPM: Unsupported package type '${packageType}' of '${arg}'")
+  endif()
+
+  set(${outArgs}
+      ${out}
+      PARENT_SCOPE
+  )
+endfunction()
+
 # Download and add a package from source
 function(CPMAddPackage)
+  list(LENGTH ARGN argnLength)
+  if(argnLength EQUAL 1)
+    cpm_parse_add_package_single_arg("${ARGN}" ARGN)
+
+    # The shorthand syntax implies EXCLUDE_FROM_ALL
+    set(ARGN "${ARGN};EXCLUDE_FROM_ALL;YES")
+  endif()
 
   set(oneValueArgs
       NAME

cmake/testing.cmake

@@ -3,7 +3,7 @@ function(ASSERT_EQUAL)
     message(FATAL_ERROR "assertion failed: invalid argument count: ${ARGC}")
   endif()
 
-  if(NOT ${ARGV0} STREQUAL ${ARGV1})
+  if(NOT "${ARGV0}" STREQUAL "${ARGV1}")
     message(FATAL_ERROR "assertion failed: '${ARGV0}' != '${ARGV1}'")
   else()
     message(STATUS "test passed: '${ARGV0}' == '${ARGV1}'")
@@ -15,7 +15,7 @@ function(ASSERT_NOT_EQUAL)
     message(FATAL_ERROR "assertion failed: invalid argument count: ${ARGC}")
   endif()
 
-  if(${ARGV0} STREQUAL ${ARGV1})
+  if("${ARGV0}" STREQUAL "${ARGV1}")
     message(FATAL_ERROR "assertion failed: '${ARGV0}' == '${ARGV1}'")
   else()
     message(STATUS "test passed: '${ARGV0}' != '${ARGV1}'")

test/unit/parse_add_package_single_arg.cmake

@@ -0,0 +1,64 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+include(${CPM_PATH}/CPM.cmake)
+include(${CPM_PATH}/testing.cmake)
+
+cpm_parse_add_package_single_arg("gh:cpm-cmake/CPM.cmake" args)
+assert_equal("GITHUB_REPOSITORY;cpm-cmake/CPM.cmake" "${args}")
+
+cpm_parse_add_package_single_arg("gh:cpm-cmake/CPM.cmake@1.2.3" args)
+assert_equal("GITHUB_REPOSITORY;cpm-cmake/CPM.cmake;VERSION;1.2.3" "${args}")
+
+cpm_parse_add_package_single_arg("gh:cpm-cmake/CPM.cmake#master" args)
+assert_equal("GITHUB_REPOSITORY;cpm-cmake/CPM.cmake;GIT_TAG;master" "${args}")
+
+cpm_parse_add_package_single_arg("gh:cpm-cmake/CPM.cmake@0.20.3#asdf" args)
+assert_equal("GITHUB_REPOSITORY;cpm-cmake/CPM.cmake;VERSION;0.20.3;GIT_TAG;asdf" "${args}")
+
+cpm_parse_add_package_single_arg("gh:a/b#c@d" args)
+assert_equal("GITHUB_REPOSITORY;a/b;GIT_TAG;c;VERSION;d" "${args}")
+
+cpm_parse_add_package_single_arg("gh:foo#c@d" args)
+assert_equal("GITHUB_REPOSITORY;foo;GIT_TAG;c;VERSION;d" "${args}")
+
+cpm_parse_add_package_single_arg("gh:Foo@5" args)
+assert_equal("GITHUB_REPOSITORY;Foo;VERSION;5" "${args}")
+
+cpm_parse_add_package_single_arg("gl:foo/bar" args)
+assert_equal("GITLAB_REPOSITORY;foo/bar" "${args}")
+
+cpm_parse_add_package_single_arg("gl:foo/Bar" args)
+assert_equal("GITLAB_REPOSITORY;foo/Bar" "${args}")
+
+cpm_parse_add_package_single_arg("https://github.com/cpm-cmake/CPM.cmake.git@0.30.5" args)
+assert_equal("GIT_REPOSITORY;https://github.com/cpm-cmake/CPM.cmake.git;VERSION;0.30.5" "${args}")
+
+cpm_parse_add_package_single_arg("git@host.xz:user/pkg.git@0.1.2" args)
+assert_equal("GIT_REPOSITORY;git@host.xz:user/pkg.git;VERSION;0.1.2" "${args}")
+
+cpm_parse_add_package_single_arg("git@host.xz:user/pkg.git@0.1.2#rc" args)
+assert_equal("GIT_REPOSITORY;git@host.xz:user/pkg.git;VERSION;0.1.2;GIT_TAG;rc" "${args}")
+
+cpm_parse_add_package_single_arg(
+  "ssh://user@host.xz:123/path/to/pkg.git#fragment@1.2.3#branch" args
+)
+assert_equal(
+  "GIT_REPOSITORY;ssh://user@host.xz:123/path/to/pkg.git#fragment;VERSION;1.2.3;GIT_TAG;branch"
+  "${args}"
+)
+
+# The following test cases are to be used in the future, once single-argument archives are supported
+
+# cpm_parse_add_package_single_arg("https://example.org/foo.tar.gz" args)
+
+# assert_equal("URL;https://example.org/foo.tar.gz" "${args}")
+
+# cpm_parse_add_package_single_arg("https://example.org/foo.tar.gz#baadf00d@1.2.0" args)
+
+# assert_equal("URL;https://example.org/foo.tar.gz;URL_HASH;baadf00d;VERSION;1.2.0" "${args}")
+
+# cpm_parse_add_package_single_arg("ftp://user:password@server/pathname.zip#fragment#0ddb411@0"
+# args)
+
+# assert_equal("URL;ftp://user:password@server/pathname.zip#fragment;URL_HASH;0ddb411;VERSION;0"
+# "${args}")