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a5c85ec822
Summary: Most of the RequestData code is platform generic, but bits of it are currently strongly tied to FUSE. By splitting these 2 parts, we will be able to use the RequestContext class in Windows too and not having to re-implement all the logic there. Reviewed By: chadaustin Differential Revision: D23482072 fbshipit-source-id: 857fd9ca4264d0f308ec10cc487e9ff3eeb5ee16
117 lines
3.7 KiB
C++
117 lines
3.7 KiB
C++
/*
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* This software may be used and distributed according to the terms of the
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* GNU General Public License version 2.
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*/
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#pragma once
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#include <folly/futures/Future.h>
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#include <atomic>
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#include <utility>
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#include "eden/fs/fuse/FuseChannel.h"
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#include "eden/fs/fuse/FuseTypes.h"
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#include "eden/fs/inodes/RequestContext.h"
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#include "eden/fs/store/ImportPriority.h"
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#include "eden/fs/store/ObjectFetchContext.h"
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#include "eden/fs/telemetry/EdenStats.h"
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#include "eden/fs/telemetry/RequestMetricsScope.h"
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namespace facebook {
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namespace eden {
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/**
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* Each FUSE request has a corresponding FuseRequestContext object that is
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* allocated at request start and deallocated when it finishes.
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*
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* Unless a member function indicates otherwise, FuseRequestContext may be used
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* from multiple threads, but only by one thread at a time.
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*/
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class FuseRequestContext : public RequestContext {
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FuseChannel* channel_;
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fuse_in_header fuseHeader_;
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fuse_in_header stealReq();
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public:
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FuseRequestContext(const FuseRequestContext&) = delete;
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FuseRequestContext& operator=(const FuseRequestContext&) = delete;
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FuseRequestContext(FuseRequestContext&&) = delete;
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FuseRequestContext& operator=(FuseRequestContext&&) = delete;
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explicit FuseRequestContext(
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FuseChannel* channel,
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const fuse_in_header& fuseHeader);
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// Override of `ObjectFetchContext`
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std::optional<pid_t> getClientPid() const override {
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return static_cast<pid_t>(fuseHeader_.pid);
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}
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// Returns the underlying fuse request, throwing an error if it has
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// already been released
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const fuse_in_header& getReq() const;
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// Returns the underlying fuse request. Unlike getReq this function doesn't
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// throw. The caller is responsible to verify that the fuse_in_header is
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// valid by checking if (fuseHeader.opcode != 0)
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const fuse_in_header& examineReq() const;
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/** Append error handling clauses to a future chain
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* These clauses result in reporting a fuse request error back to the
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* kernel. */
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folly::Future<folly::Unit> catchErrors(
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folly::Future<folly::Unit>&& fut,
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Notifications* FOLLY_NULLABLE notifications) {
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return std::move(fut).thenTryInline([this, notifications](
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folly::Try<folly::Unit>&& try_) {
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SCOPE_EXIT {
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finishRequest();
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};
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if (try_.hasException()) {
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if (auto* err = try_.tryGetExceptionObject<folly::FutureTimeout>()) {
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timeoutErrorHandler(*err, notifications);
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} else if (
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auto* err = try_.tryGetExceptionObject<std::system_error>()) {
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systemErrorHandler(*err, notifications);
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} else if (auto* err = try_.tryGetExceptionObject<std::exception>()) {
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genericErrorHandler(*err, notifications);
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} else {
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genericErrorHandler(
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std::runtime_error{"unknown exception type"}, notifications);
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}
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}
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});
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}
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void systemErrorHandler(
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const std::system_error& err,
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Notifications* FOLLY_NULLABLE notifications);
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void genericErrorHandler(
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const std::exception& err,
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Notifications* FOLLY_NULLABLE notifications);
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void timeoutErrorHandler(
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const folly::FutureTimeout& err,
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Notifications* FOLLY_NULLABLE notifications);
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template <typename T>
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void sendReply(const T& payload) {
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channel_->sendReply(stealReq(), payload);
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}
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template <typename T>
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void sendReply(T&& payload) {
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channel_->sendReply(stealReq(), std::forward<T>(payload));
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}
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// Reply with a negative errno value or 0 for success
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void replyError(int err);
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// Don't send a reply, just release req_
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void replyNone();
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};
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} // namespace eden
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} // namespace facebook
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