Don't create a snapshot in Initialize(), but leave the creation
responsibility to the cmake instance instead. Previously, the
cmState would Initialize() in its constructor, and the cmake instance
would re-Initialize() during Configure(). The end result was the
same and there would be one snapshot present. However, cmLocalGenerator
also created a snapshot on construction, and that one was used, leaving
the first snapshot unused, and potential for off-by-one errors.
Fix that by making the cmLocalGenerator use the existing snapshot
if it is top-level. Add a CurrentSnapshot to the cmake instance and
populated it while configuring a directory. This will eventually
replace the 'current local generator' concept. Fix the GetParent
implementation to be able to return the first snapshot.
There is no need to duplicate these in all cmLocalGenerators.
Rename the symbols according to current conventions.
Add explicit calls to Set{Source,Binary}Directory with empty strings
in order to trigger the population of the components containers with
the current working directory in cmLocalGenerator. Having
directories set to empty is a special case in CMake, which is relied
on for the `if(CMAKE_BINARY_DIR)` condition at the end of
CMakeDetermineSystem.cmake.
In commit 74de9a73 (cmGlobalGenerator: Delegate storage of enabled
languages to cmState, 2015-04-11) the original LanguageEnabled
member of cmGlobalGenerator was left behind by mistake. One use
of it in EnableLanguagesFromGenerator (for try_compile) was left,
but the member is not populated anymore. Drop the member and
teach EnableLanguagesFromGenerator to copy the list of enabled
languages from one cmState to the other.
Reported-by: Matt McCormick <matt.mccormick@kitware.com>
Create snapshots for buildsystem directories during configure time.
This class will be extended in follow up commits to snapshot
all values in the cmState.
At this point, it is an interface to the cache. It will be extended
to be a universal interface for access to and manipulation of
configuration-time data (defintions, properties on targets,
directories, source files etc).
This will allow porting all command implementations away
from the cmMakefile and cmTarget classes, and result in something
more-purely related to configuration-time processing of cmake
commands. That should serve at least the following goals:
* Split the CMake implementation more definitively into three
stages: Configuration, computation and generation, and be able to
implement each optimally for memory access patterns etc.
* Make better IDE integration possible by making more configuration
data available.
* Make it possiblte to use a smaller library than CMakeLib.a in
cpack and ctest, resulting in smaller executables.
* Make it possible to run the configure step multiple times in
the same CMake run (#14539).
Manage its lifetime in the cmake class, and add a convenience accessor
to cmMakefile.
Stephen Kelly
Brad King