CMakeModule to find Git (previously only Mercurial)

code/CMakeModules/FindGit.cmake

@@ -0,0 +1,106 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+#.rst:
+# FindGit
+# -------
+#
+# The module defines the following variables:
+#
+# ``GIT_EXECUTABLE``
+#   Path to Git command-line client.
+# ``Git_FOUND``, ``GIT_FOUND``
+#   True if the Git command-line client was found.
+# ``GIT_VERSION_STRING``
+#   The version of Git found.
+#
+# Example usage:
+#
+# .. code-block:: cmake
+#
+#    find_package(Git)
+#    if(Git_FOUND)
+#      message("Git found: ${GIT_EXECUTABLE}")
+#    endif()
+
+# Look for 'git' or 'eg' (easy git)
+#
+set(git_names git eg)
+
+# Prefer .cmd variants on Windows unless running in a Makefile
+# in the MSYS shell.
+#
+if(CMAKE_HOST_WIN32)
+  if(NOT CMAKE_GENERATOR MATCHES "MSYS")
+    set(git_names git.cmd git eg.cmd eg)
+    # GitHub search path for Windows
+    file(GLOB github_path
+      "$ENV{LOCALAPPDATA}/Github/PortableGit*/cmd"
+      "$ENV{LOCALAPPDATA}/Github/PortableGit*/bin"
+      )
+    # SourceTree search path for Windows
+    set(_git_sourcetree_path "$ENV{LOCALAPPDATA}/Atlassian/SourceTree/git_local/bin")
+  endif()
+endif()
+
+# First search the PATH and specific locations.
+find_program(GIT_EXECUTABLE
+  NAMES ${git_names}
+  PATHS ${github_path} ${_git_sourcetree_path}
+  DOC "Git command line client"
+  )
+
+if(CMAKE_HOST_WIN32)
+  # Now look for installations in Git/ directories under typical installation
+  # prefixes on Windows.  Exclude PATH from this search because VS 2017's
+  # command prompt happens to have a PATH entry with a Git/ subdirectory
+  # containing a minimal git not meant for general use.
+  find_program(GIT_EXECUTABLE
+    NAMES ${git_names}
+    PATH_SUFFIXES Git/cmd Git/bin
+    NO_SYSTEM_ENVIRONMENT_PATH
+    DOC "Git command line client"
+    )
+endif()
+
+mark_as_advanced(GIT_EXECUTABLE)
+
+MACRO(Git_WC_INFO dir prefix)
+    EXECUTE_PROCESS(COMMAND ${Git_EXECUTABLE} log -r --pretty=format:"%d;%H;%an" .
+      WORKING_DIRECTORY ${dir}
+      OUTPUT_VARIABLE ${prefix}_WC_INFO
+      ERROR_VARIABLE Git_info_error
+      RESULT_VARIABLE Git_info_result
+      OUTPUT_STRIP_TRAILING_WHITESPACE)
+
+    IF(NOT ${Git_info_result} EQUAL 0)
+      MESSAGE(SEND_ERROR "Command \"${GIT_EXECUTABLE} log\" failed with output:\n${Git_info_error}")
+    ELSE()
+      LIST(LENGTH ${prefix}_WC_INFO _COUNT)
+      IF(_COUNT EQUAL 4)
+        LIST(GET ${prefix}_WC_INFO 0 ${prefix}_WC_REVISION)
+        LIST(GET ${prefix}_WC_INFO 1 ${prefix}_WC_CHANGESET)
+        LIST(GET ${prefix}_WC_INFO 3 ${prefix}_WC_LAST_CHANGED_AUTHOR)
+      ELSE()
+        MESSAGE(STATUS "Bad output from HG")
+        SET(${prefix}_WC_REVISION "unknown")
+        SET(${prefix}_WC_CHANGESET "unknown")
+        SET(${prefix}_WC_BRANCH "unknown")
+      ENDIF()
+    ENDIF()
+
+  ENDMACRO()
+
+unset(git_names)
+unset(_git_sourcetree_path)
+
+if(GIT_EXECUTABLE)
+  execute_process(COMMAND ${GIT_EXECUTABLE} --version
+                  OUTPUT_VARIABLE git_version
+                  ERROR_QUIET
+                  OUTPUT_STRIP_TRAILING_WHITESPACE)
+  if (git_version MATCHES "^git version [0-9]")
+    string(REPLACE "git version " "" GIT_VERSION_STRING "${git_version}")
+  endif()
+  unset(git_version)
+endif()