From 6d6173f24738fd67b8fa4149c9d68b90b524491f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20B=C3=B8e?= <sebastian.boe@nordicsemi.no>
Date: Tue, 5 Nov 2019 16:54:20 +0100
Subject: [PATCH] cmake: Speed up CMake by not invoking 'west'
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Speed up CMake by 100ms by importing west instead of invoking it as an
executable.

There is significant overhead in invoking west as a script via
pip. The exact reason why is not clear.

Also, simplify the version output parsing as we get the version in a
more machine-readable form now.

Signed-off-by: Sebastian Bøe <sebastian.boe@nordicsemi.no>
---
 cmake/host-tools.cmake | 34 ++++++++++++++--------------------
 1 file changed, 14 insertions(+), 20 deletions(-)

diff --git a/cmake/host-tools.cmake b/cmake/host-tools.cmake
index 3c52b4c6bd..489bcecf00 100644
--- a/cmake/host-tools.cmake
+++ b/cmake/host-tools.cmake
@@ -15,31 +15,25 @@ else()
   set(MIN_WEST_VERSION 0.6.0)
   execute_process(
     COMMAND
-    ${WEST} --version
-    OUTPUT_VARIABLE west_version_output
+    ${PYTHON_EXECUTABLE}
+    -c
+    "import west.version; print(west.version.__version__, end='')"
+    OUTPUT_VARIABLE west_version
+    RESULT_VARIABLE west_version_output_result
     )
 
-  # The west --version output is currently multiline: bootstrapper
-  # followed by installation version. Test both. This will still work
-  # when .west/west is eliminated from the installation and obtained
-  # via pypi, which will result in a single line of output.
-  string(REGEX REPLACE "\n" ";" west_version_output "${west_version_output}")
-  foreach(item ${west_version_output})
-    if("${item}" MATCHES "^[^\/\\]*v([0-9]+[.][0-9]+[.][0-9]+)")
-      set(west_version "${CMAKE_MATCH_1}")
-      if(${west_version} VERSION_LESS ${MIN_WEST_VERSION})
-        message(FATAL_ERROR "The detected west version is unsupported.\n\
+  if(west_version_output_result)
+    message(FATAL_ERROR "Unable to import west.version from '${PYTHON_EXECUTABLE}'")
+  endif()
+
+  if(${west_version} VERSION_LESS ${MIN_WEST_VERSION})
+    message(FATAL_ERROR "The detected west version is unsupported.\n\
   The version was found to be ${west_version}:\n\
     ${item}\n\
   But the minimum supported version is ${MIN_WEST_VERSION}\n\
-  Please upgrade, e.g. with:\n\
-      pip3 install --upgrade west\n\
-  if the version from pip is too old, or:\n\
-      west update\n\
-  if the version in the installation is too old.")
-      endif()
-    endif()
-  endforeach()
+  Please upgrade with:\n\
+      pip3 install --upgrade west")
+  endif()
   # Just output information for a single version. This will still work
   # even after output is one line.
   message(STATUS "Found west: ${WEST} (found suitable version \"${west_version}\", minimum required is \"${MIN_WEST_VERSION}\")")