genode-ehmry/repos/libports
Norman Feske eba9c15746 Follow practices suggested by "Effective C++"
The patch adjust the code of the base, base-<kernel>, and os repository.
To adapt existing components to fix violations of the best practices
suggested by "Effective C++" as reported by the -Weffc++ compiler
argument. The changes follow the patterns outlined below:

* A class with virtual functions can no longer publicly inherit base
  classed without a vtable. The inherited object may either be moved
  to a member variable, or inherited privately. The latter would be
  used for classes that inherit 'List::Element' or 'Avl_node'. In order
  to enable the 'List' and 'Avl_tree' to access the meta data, the
  'List' must become a friend.

* Instead of adding a virtual destructor to abstract base classes,
  we inherit the new 'Interface' class, which contains a virtual
  destructor. This way, single-line abstract base classes can stay
  as compact as they are now. The 'Interface' utility resides in
  base/include/util/interface.h.

* With the new warnings enabled, all member variables must be explicitly
  initialized. Basic types may be initialized with '='. All other types
  are initialized with braces '{ ... }' or as class initializers. If
  basic types and non-basic types appear in a row, it is nice to only
  use the brace syntax (also for basic types) and align the braces.

* If a class contains pointers as members, it must now also provide a
  copy constructor and assignment operator. In the most cases, one
  would make them private, effectively disallowing the objects to be
  copied. Unfortunately, this warning cannot be fixed be inheriting
  our existing 'Noncopyable' class (the compiler fails to detect that
  the inheriting class cannot be copied and still gives the error).
  For now, we have to manually add declarations for both the copy
  constructor and assignment operator as private class members. Those
  declarations should be prepended with a comment like this:

        /*
         * Noncopyable
         */
        Thread(Thread const &);
        Thread &operator = (Thread const &);

  In the future, we should revisit these places and try to replace
  the pointers with references. In the presence of at least one
  reference member, the compiler would no longer implicitly generate
  a copy constructor. So we could remove the manual declaration.

Issue #465
2018-01-17 12:14:35 +01:00
..
doc tool: remove deprecated 'make prepare' mechanism 2016-03-17 17:02:04 +01:00
include Follow practices suggested by "Effective C++" 2018-01-17 12:14:35 +01:00
lib libc: prevent timer session if rtc not configured 2018-01-17 12:14:33 +01:00
ports Port of libarchive 2017-12-21 15:01:42 +01:00
recipes depot: recipe for stdcxx library 2017-12-22 11:43:39 +01:00
run libc: fill stdio descriptors even if invalid 2018-01-17 12:14:33 +01:00
src pthread: prevent copy of Genode::Thread object 2018-01-17 12:14:34 +01:00
README README update 2016-08-30 17:24:00 +02:00

This directory contains ports of popular 3rd-party software to Genode.


Usage
-----

The tool './tool/ports/prepare_port' in the toplevel directory automates the
task of downloading and preparing the library source codes. You can select
individual packages that have to be prepared by specifying their base names
(without the version number) as command-line argument. For example, the
following command prepares both the C library and the Freetype library:
! ./tool/ports/prepare_port libc freetype

To compile and link against 3rd-party libraries of the 'libports' repository,
you have to include the repository into the build process by appending it to the
'REPOSITORIES' declaration of your '<build-dir>/etc/build.conf' file.


Under the hood
--------------

For each library, there is a file contained in the 'libports/ports/'
subdirectory. The file is named after the library and contains the
library-specific rules for downloading the source code and installing header
files.


How does 'libports' relate to the other repositories?
-----------------------------------------------------

Most libraries hosted in the 'libports' repository expect a complete C library,
which is provided with the 'libc' package. Please do not forget to prepare the
libc package when using any of the other libports packages. The libc, in turn,
depends on the 'os' repository for its back end. Because the 'os' repository is
the home of the dynamic linker, libraries contained in 'libports' are safe to
assume the presence of the dynamic linker and, thus, should be built as shared
libraries.