From 2e0dda9e0315bbd13aa2e29c1a8a4eef8f9419ba Mon Sep 17 00:00:00 2001
From: Peter Wu <peter@lekensteyn.nl>
Date: Wed, 6 Jan 2021 20:43:37 +0100
Subject: [PATCH] CMake: Reduce "Generating plugin.c" noise during the build

With Ninja, the build is unnecessarily noisy:

    [21/81] Generating plugin.c
    Generated plugin.c for l16_mono.
    [22/81] Generating plugin.c
    Generated plugin.c for G711.

Avoid writing `Generated plugin.c for G711` and generate a single line
such as `Generating plugins/codecs/G711/plugin.c` instead.

Do not write the absolute path to plugin.c, this should hopefully help
with reproducible builds that are independent of the build directory.
---
 cmake/modules/UseMakePluginReg.cmake | 8 +++++---
 tools/make-plugin-reg.py             | 4 ++--
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/cmake/modules/UseMakePluginReg.cmake b/cmake/modules/UseMakePluginReg.cmake
index 19f0e9bf40..e6e6a9193d 100644
--- a/cmake/modules/UseMakePluginReg.cmake
+++ b/cmake/modules/UseMakePluginReg.cmake
@@ -1,9 +1,10 @@
 #
-MACRO(REGISTER_PLUGIN_FILES _outputfile _registertype )
+function(register_plugin_files _outputfile _registertype)
 	include(LocatePythonModule)
 	locate_python_module(make-plugin-reg REQUIRED PATHS ${CMAKE_SOURCE_DIR}/tools)
 
-	ADD_CUSTOM_COMMAND(
+	file(RELATIVE_PATH output "${CMAKE_BINARY_DIR}" "${CMAKE_CURRENT_BINARY_DIR}/${_outputfile}")
+	add_custom_command(
 	    OUTPUT
 	      ${_outputfile}
 	    COMMAND ${PYTHON_EXECUTABLE}
@@ -11,8 +12,9 @@ MACRO(REGISTER_PLUGIN_FILES _outputfile _registertype )
 	      ${CMAKE_CURRENT_SOURCE_DIR}
 	      ${_registertype}
 	      ${ARGN}
+	    COMMENT "Generating ${output}"
 	    DEPENDS
 	      ${ARGN}
 	      ${PY_MAKE-PLUGIN-REG}
 	)
-ENDMACRO(REGISTER_PLUGIN_FILES)
+endfunction()
diff --git a/tools/make-plugin-reg.py b/tools/make-plugin-reg.py
index 946edb8d3b..455936032a 100755
--- a/tools/make-plugin-reg.py
+++ b/tools/make-plugin-reg.py
@@ -2,6 +2,7 @@
 #
 # Looks for registration routines in the plugins
 # and assembles C code to call all the routines.
+# A new "plugin.c" file will be written in the current directory.
 #
 
 import os
@@ -28,7 +29,7 @@ preamble = """\
  *
  * Generated automatically from %s.
  */
-""" % (sys.argv[0])
+""" % (os.path.basename(sys.argv[0]))
 
 # Create the proper list of filenames
 filenames = []
@@ -165,7 +166,6 @@ try:
     fh = open(final_filename, 'w')
     fh.write(reg_code)
     fh.close()
-    print('Generated {} for {}.'.format(final_filename, os.path.basename(srcdir)))
 except OSError:
     sys.exit('Unable to write ' + final_filename + '.\n')