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downloader: use priority_queue

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This commit is contained in:
Alexander Ried 2016-10-17 23:11:04 +02:00
parent ae8884b949
commit efb938468c
1 changed files with 17 additions and 12 deletions
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29
src/libstore/download.cc
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@ -10,6 +10,7 @@
#include <curl/curl.h>
#include <queue>
#include <iostream>
#include <thread>
#include <cmath>
@ -281,8 +282,13 @@ struct CurlDownloader : public Downloader
struct State
{
struct EmbargoComparator {
bool operator() (const std::shared_ptr<DownloadItem> & i1, const std::shared_ptr<DownloadItem> & i2) {
return i1->embargo > i2->embargo;
}
};
bool quit = false;
std::vector<std::shared_ptr<DownloadItem>> incoming;
std::priority_queue<std::shared_ptr<DownloadItem>, std::vector<std::shared_ptr<DownloadItem>>, EmbargoComparator> incoming;
};
Sync<State> state_;
@ -380,9 +386,7 @@ struct CurlDownloader : public Downloader
/* Add new curl requests from the incoming requests queue,
except for requests that are embargoed (waiting for a
retry timeout to expire). FIXME: should use a priority
queue for the embargoed items to prevent repeated O(n)
checks. */
retry timeout to expire). */
if (extraFDs[0].revents & CURL_WAIT_POLLIN) {
char buf[1024];
auto res = read(extraFDs[0].fd, buf, sizeof(buf));
@ -390,22 +394,23 @@ struct CurlDownloader : public Downloader
throw SysError("reading curl wakeup socket");
}
std::vector<std::shared_ptr<DownloadItem>> incoming, embargoed;
std::vector<std::shared_ptr<DownloadItem>> incoming;
auto now = std::chrono::steady_clock::now();
{
auto state(state_.lock());
for (auto & item: state->incoming) {
if (item->embargo <= now)
while (!state->incoming.empty()) {
auto item = state->incoming.top();
if (item->embargo <= now) {
incoming.push_back(item);
else {
embargoed.push_back(item);
state->incoming.pop();
} else {
if (nextWakeup == std::chrono::steady_clock::time_point()
|| item->embargo < nextWakeup)
nextWakeup = item->embargo;
break;
}
}
state->incoming = embargoed;
quit = state->quit;
}
@ -432,7 +437,7 @@ struct CurlDownloader : public Downloader
{
auto state(state_.lock());
state->incoming.clear();
while (!state->incoming.empty()) state->incoming.pop();
state->quit = true;
}
}
@ -443,7 +448,7 @@ struct CurlDownloader : public Downloader
auto state(state_.lock());
if (state->quit)
throw nix::Error("cannot enqueue download request because the download thread is shutting down");
state->incoming.push_back(item);
state->incoming.push(item);
}
writeFull(wakeupPipe.writeSide.get(), " ");
}