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feat(xworkspaces): Support occupied workspaces (#882)

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A workspace is occupied if it is not active and there is at least one window managed by the WM (`_NET_CLIENT_LIST`) that has set `_NET_WM_DESKTOP` to that workspace.

The behavior when `_NET_WM_DESKTOP` is not set is not yet clear but this is unlikely to happen since most WMs will position windows on some desktop.

Closes #874
Fixes #1444
Fixes #1033 

* Set Desktop OCCUPIED if a window moves there

This covers more of an edge-case. I did this first by accident, it might
vanish later on.

* Replace tracking change of WS with currently used WS

* Untrack occupied workspaces

* Track windows and their desktops in pairs

* Match type of occupied_desktops with current_desktop

Because the index needs to be matched later on, type mismatches would be non-ideal.

* Recreate the occupied desktops everytime and remove duplicates

* Readd support for moving windows to other desktops

* Use less characters to empty the vector

* Rename variable storing the desktops

* Recount windows on every occasion

This alone simplifies the management and the lookup for occupation of a
workspace

* Keep track of number of windows in every workspace

* Add debugging output that shall be removed before merging

* Remove obsolete TODO

* m_client_list should always be diff'd, since the desktop may change

Therefore we update the desktop-count tally every time the client_list
changes. It may just be a desktop-change without a change of
clients.size()...

* Add more logging-spam to understand window/desktop lifecycle

* Lock event-handler to serialize handling of events

* Fix occupied workspace counting and change to bool array

Also, performance improvements when diffing new and old client lists

* Fix crash when all clients are removed

* Conform to linter and styleguide

* Shorten conditional as it is standard enough

Since this only guards against 0-divisions, it can be shortened
without risking too much confusion down the road.

* Guard against multiple threads accessing and modifying data

Fixes #1444

Modification of internal data happens through the handle-method, while
the build-method tries to access the data structures for display. Since
some modifications clear e.g. the m_viewports, references may become
invalid between looping over them an accessing them.

The mutex should guard against this simultanuous access.

* Do not 'adopt_lock', because calls come from very different threads

To my understanding, adopt_lock has some dependency on the mutex-ownership. Since
the lock is once called from the inside (in handle) and once from the outside (in
build), there might be a problem. After brief testing, the segfaults happened fewer
times.

See #1444

* Also listen to _NET_WM_DESKTOP

In order to move a window from one desktop to another, it is sufficient
to set the desktop-property of that window. xmonad fires a lot of events
in the case of moving a window, herbstluftwm only updates the
_NET_WM_DESKTOP-atom of the window.

This change reloads the clientlist in order to correctly set the
desktop state "occupied".

* Describe need and use of mutex

It might be possible to relieve the guard in xworkspaces_module::handle,
but I am unsure about this. Since xmonad emits a lot of events on almost
every minor change, I would let the guard keep its post, avoiding
race-conditions in event-handling.

* Give temporary variables better names

* Clarify purpose of loop

About 80% of this comment are taken from
https://github.com/jaagr/polybar/pull/882#discussion_r255317363

* Remove merge-remainder

* Use a simpler method to list occupied desktops.

Co-authored-by: Jérôme Boulmier <jerome.boulmier@outlook.fr>

* Document m_clients field
This commit is contained in:
Matthias Viehweger 2019-10-21 10:00:38 +02:00 committed by Patrick Ziegler
parent 4ab251f33c
commit 52f0623315
2 changed files with 52 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
include/modules/xworkspaces.hpp
View File

@ -1,6 +1,8 @@
#pragma once
#include <bitset>
#include <mutex>
#include <set>
#include "components/config.hpp"
#include "components/types.hpp"
@ -69,9 +71,10 @@ namespace modules {
void set_desktop_urgent(xcb_window_t window);
bool input(string&& cmd);
vector<string> get_desktop_names();
private:
static vector<string> get_desktop_names();
static constexpr const char* DEFAULT_ICON{"icon-default"};
static constexpr const char* DEFAULT_LABEL_STATE{"%icon% %name%"};
static constexpr const char* DEFAULT_LABEL_MONITOR{"%name%"};
@ -94,7 +97,10 @@ namespace modules {
unsigned int m_current_desktop;
string m_current_desktop_name;
vector<xcb_window_t> m_clientlist;
/**
* Maps an xcb window to its desktop number
*/
map<xcb_window_t, unsigned int> m_clients;
vector<unique_ptr<viewport>> m_viewports;
map<desktop_state, label_t> m_labels;
label_t m_monitorlabel;
@ -104,8 +110,12 @@ namespace modules {
bool m_scroll{true};
size_t m_index{0};
// The following mutex is here to protect the data of this modules.
// This can't be achieved using m_buildlock since we "CRTP override" get_output().
mutable mutex m_workspace_mutex;
event_timer m_timer{0L, 25L};
};
}
} // namespace modules
POLYBAR_NS_END

71
src/modules/xworkspaces.cpp
View File

@ -1,9 +1,10 @@
#include "modules/xworkspaces.hpp"
#include <algorithm>
#include <utility>
#include "drawtypes/iconset.hpp"
#include "drawtypes/label.hpp"
#include "modules/xworkspaces.hpp"
#include "utils/factory.hpp"
#include "utils/math.hpp"
#include "x11/atoms.hpp"
@ -17,7 +18,7 @@ namespace {
inline bool operator==(const position& a, const position& b) {
return a.x + a.y == b.x + b.y;
}
}
} // namespace
namespace modules {
template class module<xworkspaces_module>;
@ -86,21 +87,25 @@ namespace modules {
m_current_desktop_name = m_desktop_names[m_current_desktop];
rebuild_desktops();
rebuild_desktop_states();
// Get _NET_CLIENT_LIST
rebuild_clientlist();
rebuild_desktop_states();
}
/**
* Handler for XCB_PROPERTY_NOTIFY events
*/
void xworkspaces_module::handle(const evt::property_notify& evt) {
if (evt->atom == m_ewmh->_NET_CLIENT_LIST) {
std::lock_guard<std::mutex> lock(m_workspace_mutex);
if (evt->atom == m_ewmh->_NET_CLIENT_LIST || evt->atom == m_ewmh->_NET_WM_DESKTOP) {
rebuild_clientlist();
rebuild_desktop_states();
} else if (evt->atom == m_ewmh->_NET_DESKTOP_NAMES || evt->atom == m_ewmh->_NET_NUMBER_OF_DESKTOPS) {
m_desktop_names = get_desktop_names();
rebuild_desktops();
rebuild_clientlist();
rebuild_desktop_states();
} else if (evt->atom == m_ewmh->_NET_CURRENT_DESKTOP) {
m_current_desktop = ewmh_util::get_current_desktop();
@ -123,28 +128,21 @@ namespace modules {
* Rebuild the list of managed clients
*/
void xworkspaces_module::rebuild_clientlist() {
vector<xcb_window_t> clients = ewmh_util::get_client_list();
vector<xcb_window_t> diff;
std::sort(clients.begin(), clients.end());
std::sort(m_clientlist.begin(), m_clientlist.end());
vector<xcb_window_t> newclients = ewmh_util::get_client_list();
std::sort(newclients.begin(), newclients.end());
if (m_clientlist.size() > clients.size()) {
std::set_difference(
m_clientlist.begin(), m_clientlist.end(), clients.begin(), clients.end(), back_inserter(diff));
for (auto&& win : diff) {
// untrack window
m_clientlist.erase(std::remove(m_clientlist.begin(), m_clientlist.end(), win), m_clientlist.end());
}
} else {
std::set_difference(
clients.begin(), clients.end(), m_clientlist.begin(), m_clientlist.end(), back_inserter(diff));
for (auto&& win : diff) {
// listen for wm_hint (urgency) changes
m_connection.ensure_event_mask(win, XCB_EVENT_MASK_PROPERTY_CHANGE);
// track window
m_clientlist.emplace_back(win);
for (auto&& client : newclients) {
if (m_clients.count(client) == 0) {
// new client: listen for changes (wm_hint or desktop)
m_connection.ensure_event_mask(client, XCB_EVENT_MASK_PROPERTY_CHANGE);
}
}
// rebuild entire mapping of clients to desktops
m_clients.clear();
for (auto&& client : newclients) {
m_clients[client] = ewmh_util::get_desktop_from_window(client);
}
}
/**
@ -209,13 +207,20 @@ namespace modules {
* Update active state of current desktops
*/
void xworkspaces_module::rebuild_desktop_states() {
std::set<unsigned int> occupied_desks;
for (auto&& c : m_clients) {
occupied_desks.insert(c.second);
}
for (auto&& v : m_viewports) {
for (auto&& d : v->desktops) {
if (m_desktop_names[d->index] == m_current_desktop_name) {
d->state = desktop_state::ACTIVE;
} else if (occupied_desks.count(d->index) > 0) {
d->state = desktop_state::OCCUPIED;
} else {
d->state = desktop_state::EMPTY;
}
}
d->label = m_labels.at(d->state)->clone();
d->label->reset_tokens();
@ -226,14 +231,13 @@ namespace modules {
}
}
vector<string> xworkspaces_module::get_desktop_names(){
vector<string> xworkspaces_module::get_desktop_names() {
vector<string> names = ewmh_util::get_desktop_names();
unsigned int desktops_number = ewmh_util::get_number_of_desktops();
if(desktops_number == names.size()) {
if (desktops_number == names.size()) {
return names;
}
else if(desktops_number < names.size()) {
names.erase(names.begin()+desktops_number, names.end());
} else if (desktops_number < names.size()) {
names.erase(names.begin() + desktops_number, names.end());
return names;
}
for (unsigned int i = names.size(); i < desktops_number + 1; i++) {
@ -247,7 +251,7 @@ namespace modules {
*/
void xworkspaces_module::set_desktop_urgent(xcb_window_t window) {
auto desk = ewmh_util::get_desktop_from_window(window);
if(desk == m_current_desktop)
if (desk == m_current_desktop)
// ignore if current desktop is urgent
return;
for (auto&& v : m_viewports) {
@ -264,7 +268,6 @@ namespace modules {
}
}
}
}
/**
@ -276,6 +279,8 @@ namespace modules {
* Generate module output
*/
string xworkspaces_module::get_output() {
std::unique_lock<std::mutex> lock(m_workspace_mutex);
// Get the module output early so that
// the format prefix/suffix also gets wrapped
// with the cmd handlers
@ -335,6 +340,8 @@ namespace modules {
* Handle user input event
*/
bool xworkspaces_module::input(string&& cmd) {
std::lock_guard<std::mutex> lock(m_workspace_mutex);
size_t len{strlen(EVENT_PREFIX)};
if (cmd.compare(0, len, EVENT_PREFIX) != 0) {
return false;
@ -372,6 +379,6 @@ namespace modules {
return true;
}
}
} // namespace modules
POLYBAR_NS_END