This makes it so that sub-packages are resolved relative to their parent's
`__path__`, rather than re-resolving each parent's filesystem path.
The previous behavior was that `import foo.bar` would first re-search
`sys.path` for `foo`, then use the resulting path to find `bar`.
For already-loaded and u-prefixed modules, because we no longer need to
build the path from level to level, we no longer unnecessarily search
the filesystem. This should improve startup time.
Explicitly makes the resolving process clear:
- Loaded modules are returned immediately without touching the filesystem.
- Exact-match of builtins are also returned immediately.
- Then the filesystem search happens.
- If that fails, then the weak-link handling is applied.
This maintains the existing behavior: if a user writes `import time` they
will get time.py if it exits, otherwise the built-in utime. Whereas `import
utime` will always return the built-in.
This also fixes a regression from a7fa18c203
where we search the filesystem for built-ins. It is now only possible to
override u-prefixed builtins. This will remove a lot of filesystem stats
at startup, as micropython-specific modules (e.g. `pyb`) will no longer
attempt to look at the filesystem.
Added several improvements to the comments and some minor renaming and
refactoring to make it clearer how the import mechanism works. Overall
code size diff is +56 bytes on STM32.
This work was funded through GitHub Sponsors.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
This commit adds generic support for mutable module attributes on built in
modules, by adding support for an optional hook function for module
attribute lookup. If a module wants to support additional attribute load/
store/delete (beyond what is in the constant, globals dict) then it should
add at the very end of its globals dict MP_MODULE_ATTR_DELEGATION_ENTRY().
This should point to a custom function which will handle any additional
attributes.
The mp_module_generic_attr() function is provided as a helper function for
additional attributes: it requires an array of qstrs (terminated in
MP_QSTRnull) and a corresponding array of objects (with a 1-1 mapping
between qstrs and objects). If the qstr is found in the array then the
corresponding object is loaded/stored/deleted.
Signed-off-by: Damien George <damien@micropython.org>
This commit implements automatic module weak links for all built-in
modules, by searching for "ufoo" in the built-in module list if "foo"
cannot be found. This means that all modules named "ufoo" are always
available as "foo". Also, a port can no longer add any other weak links,
which makes strict the definition of a weak link.
It saves some code size (about 100-200 bytes) on ports that previously had
lots of weak links.
Some changes from the previous behaviour:
- It doesn't intern the non-u module names (eg "foo" is not interned),
which saves code size, but will mean that "import foo" creates a new qstr
(namely "foo") in RAM (unless the importing module is frozen).
- help('modules') no longer lists non-u module names, only the u-variants;
this reduces duplication in the help listing.
Weak links are effectively the same as having a set of symbolic links on
the filesystem that is searched last. So an "import foo" will search
built-in modules first, then all paths in sys.path, then weak links last,
importing "ufoo" if it exists. Thus a file called "foo.py" somewhere in
sys.path will still have precedence over the weak link of "foo" to "ufoo".
See issues: #1740, #4449, #5229, #5241.
The code conventions suggest using header guards, but do not define how
those should look like and instead point to existing files. However, not
all existing files follow the same scheme, sometimes omitting header guards
altogether, sometimes using non-standard names, making it easy to
accidentally pick a "wrong" example.
This commit ensures that all header files of the MicroPython project (that
were not simply copied from somewhere else) follow the same pattern, that
was already present in the majority of files, especially in the py folder.
The rules are as follows.
Naming convention:
* start with the words MICROPY_INCLUDED
* contain the full path to the file
* replace special characters with _
In addition, there are no empty lines before #ifndef, between #ifndef and
one empty line before #endif. #endif is followed by a comment containing
the name of the guard macro.
py/grammar.h cannot use header guards by design, since it has to be
included multiple times in a single C file. Several other files also do not
need header guards as they are only used internally and guaranteed to be
included only once:
* MICROPY_MPHALPORT_H
* mpconfigboard.h
* mpconfigport.h
* mpthreadport.h
* pin_defs_*.h
* qstrdefs*.h
They are one-line functions and having them inline in mp_init/mp_deinit
eliminates the overhead of a function call, and matches how other state
is initialised in mp_init.
Blanket wide to all .c and .h files. Some files originating from ST are
difficult to deal with (license wise) so it was left out of those.
Also merged modpyb.h, modos.h, modstm.h and modtime.h in stmhal/.
Jim Mussared
Damien George
Damien George
Alexander Steffen