mirror of https://github.com/polybar/polybar.git
95 lines
2.2 KiB
C++
95 lines
2.2 KiB
C++
#pragma once
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#include <cassert>
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#include <stdexcept>
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#include <unordered_map>
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#include "common.hpp"
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POLYBAR_NS
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/**
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* Maps action names to function pointers in this module and invokes them.
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*
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* Each module has one instance of this class and uses it to register action.
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* For each action the module has to register the name, whether it can take
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* additional data, and a pointer to the member function implementing that
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* action.
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*
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* Ref: https://isocpp.org/wiki/faq/pointers-to-members
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*
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* The input() function in the base class uses this for invoking the actions
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* of that module.
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*
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* Any module that does not reimplement that function will automatically use
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* this class for action routing.
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*/
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template <typename Impl>
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class action_router {
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typedef void (Impl::*callback)();
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typedef void (Impl::*callback_data)(const std::string&);
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public:
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explicit action_router(Impl* This) : m_this(This) {}
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void register_action(const string& name, callback func) {
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entry e;
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e.with_data = false;
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e.without = func;
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register_entry(name, e);
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}
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void register_action_with_data(const string& name, callback_data func) {
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entry e;
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e.with_data = true;
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e.with = func;
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register_entry(name, e);
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}
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bool has_action(const string& name) {
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return callbacks.find(name) != callbacks.end();
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}
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/**
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* Invokes the given action name on the passed module pointer.
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*
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* The action must exist.
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*/
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void invoke(const string& name, const string& data) {
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auto it = callbacks.find(name);
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assert(it != callbacks.end());
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entry e = it->second;
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#define CALL_MEMBER_FN(object, ptrToMember) ((object).*(ptrToMember))
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if (e.with_data) {
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CALL_MEMBER_FN(*m_this, e.with)(data);
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} else {
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CALL_MEMBER_FN(*m_this, e.without)();
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}
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#undef CALL_MEMBER_FN
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}
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protected:
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struct entry {
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union {
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callback without;
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callback_data with;
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};
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bool with_data;
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};
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void register_entry(const string& name, const entry& e) {
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if (has_action(name)) {
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throw std::invalid_argument("Tried to register action '" + name + "' twice. THIS IS A BUG!");
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}
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callbacks[name] = e;
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}
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private:
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std::unordered_map<string, entry> callbacks;
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Impl* m_this;
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};
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POLYBAR_NS_END
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