[cmake-developers] [CMake 0014729]: Support "custom cmake generator"

[Mantis Bug Tracker]

The following issue has been SUBMITTED. 
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http://www.cmake.org/Bug/view.php?id=14729 
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Reported By:                NAKAMURA Takumi
Assigned To:                
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Project:                    CMake
Issue ID:                   14729
Category:                   CMake
Reproducibility:            N/A
Severity:                   feature
Priority:                   normal
Status:                     new
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Date Submitted:             2014-02-03 00:44 EST
Last Modified:              2014-02-03 00:44 EST
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Summary:                    Support "custom cmake generator"
Description: 
Experimentally I am writing "Custom generator". This is intended for auto
dependency scanner.

It doesn't work, at least with Ninja Generator.
As far as I see build.ninja, a few issues...

1) "ninja -t clean" removes foo.cmake.

  It's Ninja's behavior. To avoid this, another rule should be added for
custom_command that touches generated cmakefiles (included by CMakeLists).
  For example,

  rule CUSTOM_GENERATOR
    command = $COMMAND
    description = $DESC
    restat = 1
    generator = 1

2) foo.cmake is added to phony target list, "A missing CMake input file is not
an error.", although foo.cmake has a rule.

  Output of custom_command should be excluded from phony targets even if it were
included from CMakeLists.

3) Also generator-dependent file, for example foobar.c might be put into phony
list, or Ninja could not rebuild build.ninja when foobar.c were disappeared (in
revision walking).

Steps to Reproduce: 
cmake_minimum_required(VERSION 2.8)

# It's supposed:
#   - Scan dependent file(s).
#   - Update when something happened. ;)
#     For now, manually update tmpl.txt.

# "touch foobar.c" doesn't trigger regeneration.
# "echo >> tmpl.txt; touch foobar.c" triggers regeneration.

add_custom_command(OUTPUT foo.cmake
  COMMAND ${CMAKE_COMMAND} -E copy_if_different
  ${CMAKE_CURRENT_SOURCE_DIR}/tmpl.txt
  ${CMAKE_CURRENT_BINARY_DIR}/foo.cmake
  DEPENDS foobar.c
  COMMENT "Updating foo.cmake"
  )
add_custom_target(theGenerator DEPENDS foo.cmake)

execute_process(
  COMMAND ${CMAKE_COMMAND} -E copy
  ${CMAKE_CURRENT_SOURCE_DIR}/tmpl.txt
  ${CMAKE_CURRENT_BINARY_DIR}/foo.cmake
  )

include(${CMAKE_CURRENT_BINARY_DIR}/foo.cmake)

add_executable(foobar foobar.c)

# Almost all targets may depend on theGenerator.
add_dependencies(foobar theGenerator)
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Issue History 
Date Modified    Username       Field                    Change               
====================================================================== 
2014-02-03 00:44 NAKAMURA TakumiNew Issue                                    
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