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Simplify the callback mechanism

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This commit is contained in:
Eelco Dolstra 2018-03-27 22:16:01 +02:00
parent 1672bcd230
commit 81ea8bd5ce
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16 changed files with 152 additions and 180 deletions
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55
src/libutil/util.hh
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@ -15,6 +15,7 @@
#include <map>
#include <sstream>
#include <experimental/optional>
#include <future>
#ifndef HAVE_STRUCT_DIRENT_D_TYPE
#define DT_UNKNOWN 0
@ -424,44 +425,30 @@ string get(const T & map, const string & key, const string & def = "")
}
/* Call ‘failure’ with the current exception as argument. If ‘failure’
throws an exception, abort the program. */
void callFailure(const std::function<void(std::exception_ptr exc)> & failure,
std::exception_ptr exc = std::current_exception());
/* Evaluate the function ‘f’. If it returns a value, call ‘success’
with that value as its argument. If it or ‘success’ throws an
exception, call ‘failure’. If ‘failure’ throws an exception, abort
the program. */
template<class T>
void sync2async(
const std::function<void(T)> & success,
const std::function<void(std::exception_ptr exc)> & failure,
const std::function<T()> & f)
/* A callback is a wrapper around a lambda that accepts a valid of
type T or an exception. (We abuse std::future<T> to pass the value or
exception.) */
template<typename T>
struct Callback
{
try {
success(f());
} catch (...) {
callFailure(failure);
}
}
std::function<void(std::future<T>)> fun;
Callback(std::function<void(std::future<T>)> fun) : fun(fun) { }
/* Call the function ‘success’. If it throws an exception, call
‘failure’. If that throws an exception, abort the program. */
template<class T>
void callSuccess(
const std::function<void(T)> & success,
const std::function<void(std::exception_ptr exc)> & failure,
T && arg)
{
try {
success(arg);
} catch (...) {
callFailure(failure);
void operator()(T && t) const
{
std::promise<T> promise;
promise.set_value(std::move(t));
fun(promise.get_future());
}
}
void rethrow(const std::exception_ptr & exc = std::current_exception()) const
{
std::promise<T> promise;
promise.set_exception(exc);
fun(promise.get_future());
}
};
/* Start a thread that handles various signals. Also block those signals