Besides adapting the components to the use of base/log.h, the patch
cleans up a few base headers, i.e., it removes unused includes from
root/component.h, specifically base/heap.h and
ram_session/ram_session.h. Hence, components that relied on the implicit
inclusion of those headers have to manually include those headers now.
While adjusting the log messages, I repeatedly stumbled over the problem
that printing char * arguments is ambiguous. It is unclear whether to
print the argument as pointer or null-terminated string. To overcome
this problem, the patch introduces a new type 'Cstring' that allows the
caller to express that the argument should be handled as null-terminated
string. As a nice side effect, with this type in place, the optional len
argument of the 'String' class could be removed. Instead of supplying a
pair of (char const *, size_t), the constructor accepts a 'Cstring'.
This, in turn, clears the way let the 'String' constructor use the new
output mechanism to assemble a string from multiple arguments (and
thereby getting rid of snprintf within Genode in the near future).
To enforce the explicit resolution of the char * ambiguity, the 'char *'
overload of the 'print' function is marked as deleted.
Issue #1987
The modular lx_kit seperates the required back end functionality of the
Linux emulation environment from the front end. Thereby each driver can
reuse specific parts or supply more suitable implementations by itself.
It is used to reduce the amount of redundant code in each driver.
The lx_kit is split into several layers whose structure is as follows:
The first layer in _repos/dde_linux/src/include/lx_emul_ contains those
header files that provide the structural definitions and function
declarations of the Linux API, e.g. _errno.h_ provides all error code
values. The second layer in _repos/dde_linux/src/include/lx_emul/impl_
contains the implementation of selected functions, e.g. _slab.h_
provides the implementation of 'kmalloc()'. The lx_kit back end API is
the third layer and provides the _Lx::Malloc_ interface
(_repos/dde_linux/src/include/lx_kit/malloc.h_) which is used to
implement 'kmalloc()'. There are several generic implementations of the
lx_kit interfaces that can be used by a driver.
A driver typically includes a 'lx_emul/impl/xyz.h' header once
directly in its lx_emul compilation unit. The lx_kit interface files
are only included in those compilation units that use or implement the
interface. If a driver wants to use a generic implementation it must
add the source file to its source file list. The generic
implementations are located in _repos/dde_linux/src/lx_kit/_.
The modular lx_kit still depends on the private _lx_emul.h_ header file
that is tailored to each driver. Since the lx_kit already contains much
of the declarations and definitions that were originally placed in
these private header files, those files can now ommit a large amount
of code.
Fixes#1974.
