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52a4ccc1bd
Rewrite the pager mechanism to make it a (parametrized) instance of `Logger` rather than being a standalone thing. The main interest of this is that we have more control over when to actually start it and make the inner pager more quiet (only when `writeToStdout` is called)
90 lines
2.4 KiB
C++
90 lines
2.4 KiB
C++
#include "paged-logger.hh"
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#include <iostream>
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namespace nix {
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PagedLogger::PagedLogger(Logger * previousLogger)
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: innerLogger(previousLogger)
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{
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}
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PagedLogger::~PagedLogger()
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{
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try {
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if (pid != -1) {
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std::cout.flush();
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dup2(stdout, STDOUT_FILENO);
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pid.wait();
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}
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} catch (...) {
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ignoreException();
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}
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}
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void PagedLogger::startPager() {
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if (pagerStarted) {
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return;
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}
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innerLogger = makeSimpleLogger(false);
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pagerStarted = true;
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if (!isatty(STDOUT_FILENO)) return;
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char * pager = getenv("NIX_PAGER");
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if (!pager) pager = getenv("PAGER");
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if (pager && ((std::string) pager == "" || (std::string) pager == "cat")) return;
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Pipe toPager;
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toPager.create();
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pid = startProcess([&]() {
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if (dup2(toPager.readSide.get(), STDIN_FILENO) == -1)
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throw SysError("dupping stdin");
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if (!getenv("LESS"))
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setenv("LESS", "FRSXMK", 1);
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restoreProcessContext();
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if (pager)
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execl("/bin/sh", "sh", "-c", pager, nullptr);
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execlp("pager", "pager", nullptr);
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execlp("less", "less", nullptr);
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execlp("more", "more", nullptr);
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throw SysError("executing '%1%'", pager);
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});
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pid.setKillSignal(SIGINT);
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pid.setKillSignal(SIGINT);
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stdout = fcntl(STDOUT_FILENO, F_DUPFD_CLOEXEC, 0);
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if (dup2(toPager.writeSide.get(), STDOUT_FILENO) == -1)
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throw SysError("dupping stdout");
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}
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void PagedLogger::writeToStdout(std::string_view s)
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{
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startPager();
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innerLogger->writeToStdout(s);
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}
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void PagedLogger::stop() { return innerLogger->stop(); }
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bool PagedLogger::isVerbose() { return false; }
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void PagedLogger::log(Verbosity lvl, const std::string_view s)
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{ innerLogger->log(lvl, s); }
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void PagedLogger::logEI(const ErrorInfo & ei) { innerLogger->logEI(ei); }
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void PagedLogger::warn(const std::string & msg)
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{ innerLogger->warn(msg); }
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void PagedLogger::startActivity(
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ActivityId act,
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Verbosity lvl,
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ActivityType type,
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const std::string & s,
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const Fields & fields,
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ActivityId parent)
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{ innerLogger->startActivity(act, lvl, type, s, fields, parent); }
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void PagedLogger::stopActivity(ActivityId act)
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{ innerLogger->stopActivity(act); }
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void PagedLogger::result(ActivityId act, ResultType type, const Fields & fields)
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{ innerLogger->result(act, type, fields); }
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std::optional<char> PagedLogger::ask(std::string_view s)
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{ return innerLogger->ask(s); }
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}
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