ImageViewer used two different logic to resize the display window, which
leads to confusing behaviour for rotate function. Now all the resizing
behaviour goes through the existing resize_window function.
KBufferBuilder is always allowed to expand if it wants to. This
restriction was added a long time ago when it was unsafe to allocate
VM while generating ProcFS contents.
Use a Mutex instead of a SpinLock to protect the per-FileDescription
generated data cache. This allows processes to go to sleep while
waiting their turn.
Also don't try to be clever by reusing existing cache buffers.
Just allocate KBuffers as needed (and make sure to surface failures.)
KBufferBuilder exists for code that wants to build a KBuffer instead
of a String. KBuffer is backed by anonymous VM, while String is backed
by a kernel heap allocation.
Advisory locks don't actually prevent other processes from writing to
the file, but they do prevent other processes looking to acquire and
advisory lock on the file.
This implementation currently only adds non-blocking locks, which are
all I need for now.
Previously, we were generating the display update one character at a
time, and writing them one at a time to stderr, which is not buffered,
doing so caused one syscall per character printed which is s l o w (TM)
This commit makes LibLine write the update contents into a buffer, and
flush it after all the update is generated :^)
While under insert mode, Ctrl-U deletes all characters between the first
non-blank character of the line and the cursor.
Implement delete_from_line_start_to_cursor() in TextEditor. Then, call
the method in VimEditingEngine via its pointer to an instance of
TextEditor.
In Vim, Ctrl-H is effectively equivalent to backspace in insert mode, as
it deletes the previous character.
This commit implements method delete_previous_char() to TextEditor.
delete_char() already exists in EditingEngine, but it deletes the
next character rather than the previous. delete_previous_char() is then
called from within VimEditingEngine.
In Vim's insert mode, Ctrl-W deletes the word before the cursor, like
Ctrl-Backspace. Unlike Ctrl-Backspace, if only whitespace exists between
the end of the word and the cursor, the word will be deleted with the
whitespace.
To do so, this commit introduces two methods: delete_previous_word() for
TextEditor and first_word_before() for TextDocument, where the former
depends on the latter. delete_previous_word() is then called in
VimEditingEngine.
Before we start disabling acquisition of the big process lock for
specific syscalls, make sure to document and assert that all the
lock is held during all syscalls.
There are cases where we want to conditionally take a lock, but still
would like to use an RAII type to make sure we don't leak the lock.
This was previously impossible to do with `MutexLocker` due to it's
design. This commit tweaks the design to allow the object to be
initialized to an "empty" state without a lock associated, so it does
nothing, and then later a lock can be "attached" to the locker.
I realized that the get_lock() API's where also unused, and would no
longer make sense for empty locks, so they were removed.
Move these to MM to simplify the flow of the syscall handler.
While here, also make sure we hold the process space lock for
the duration of the validation to avoid potential issues where
another thread attempts to modify the process space during the
validation. This will allow us to move the validation out of the
big process lock scope in a future change.
Additionally utilize the new no_lock variants of functions to avoid
unnecessary recursive process space spinlock acquisitions.
