/*
 * AsyncFileEIO.actor.h
 *
 * This source file is part of the FoundationDB open source project
 *
 * Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#if defined(__unixish__)

#define Net2AsyncFile AsyncFileEIO

// When actually compiled (NO_INTELLISENSE), include the generated version of this file.  In intellisense use the source version.
#if defined(NO_INTELLISENSE) && !defined(FLOW_ASYNCFILEEIO_ACTOR_G_H)
	#define FLOW_ASYNCFILEEIO_ACTOR_G_H
	#include "AsyncFileEIO.actor.g.h"
#elif !defined(FLOW_ASYNCFILEEIO_ACTOR_H)
	#define FLOW_ASYNCFILEEIO_ACTOR_H

#include "eio.h"
#include "flow/flow.h"
#include "flow/ThreadHelper.actor.h"
#include "IAsyncFile.h"
#include "flow/TDMetric.actor.h"

#include <fcntl.h>
#include <sys/stat.h>

class AsyncFileEIO : public IAsyncFile, public ReferenceCounted<AsyncFileEIO> {

public:
	static void init() {
		if (eio_init( &eio_want_poll, NULL )) { 
			TraceEvent("EioInitError").detail("ErrorNo", errno);
			throw platform_error(); 
		}
	}

	static bool should_poll() { return want_poll; }

	static bool lock_fd( int fd ) {
		// Acquire a "write" lock for the entire file
		struct flock lockDesc;
		lockDesc.l_type = F_WRLCK;
		lockDesc.l_whence = SEEK_SET;
		lockDesc.l_start = 0;
		lockDesc.l_len = 0;  // "Specifying 0 for l_len has the special meaning: lock all bytes starting at the location specified by l_whence and l_start through to the end of file, no matter how large the file grows."
		lockDesc.l_pid = 0;
		if (fcntl(fd, F_SETLK, &lockDesc) == -1) {
			return false;
		}
		return true;
	}

	ACTOR static Future<Reference<IAsyncFile>> open( std::string filename, int flags, int mode, void* ignore ) {
		std::string open_filename = filename;
		if (flags & OPEN_ATOMIC_WRITE_AND_CREATE) {
			ASSERT( (flags & OPEN_CREATE) && (flags & OPEN_READWRITE) && !(flags & OPEN_EXCLUSIVE) );
			open_filename = filename + ".part";
		}

		state Promise<Void> p;
		state eio_req* r = eio_open( open_filename.c_str(), openFlags(flags), mode, 0, eio_callback, &p );
		try { Void _ = wait( p.getFuture() ); } catch (...) { eio_cancel(r); throw; }
		if (r->result < 0) {
			errno = r->errorno;
			bool notFound = errno == ENOENT;
			Error e = notFound ? file_not_found() : io_error();
			TraceEvent(notFound ? SevWarn : SevWarnAlways, "FileOpenError").error(e).GetLastError().detail("File", filename).detail("Flags", flags).detail("Mode", mode);
			throw e;
		}
		TraceEvent("AsyncFileOpened").detail("Filename", filename).detail("fd", r->result).detail("Flags", flags).suppressFor(1.0);

		if ((flags & OPEN_LOCK) && !lock_fd(r->result)) {
			TraceEvent(SevError, "UnableToLockFile").detail("filename", filename).GetLastError();
			throw io_error();
		}

		return Reference<IAsyncFile>(new AsyncFileEIO( r->result, flags, filename ));
	}
	static Future<Void> deleteFile( std::string filename, bool mustBeDurable ) {
		::deleteFile(filename);
		if (mustBeDurable) {
			TEST(true); // deleteFile and fsync parent dir
			return async_fsync_parent( filename );
		} else
			return Void();
	}

	virtual void addref() { ReferenceCounted<AsyncFileEIO>::addref(); }
	virtual void delref() { ReferenceCounted<AsyncFileEIO>::delref(); }

	virtual int64_t debugFD() { return fd; }

	virtual Future<int> read( void* data, int length, int64_t offset ) {
		++countFileLogicalReads;
		++countLogicalReads;
		return read_impl(fd, data, length, offset);
	}
	virtual Future<Void> write( void const* data, int length, int64_t offset ) // Copies data synchronously
	{
		++countFileLogicalWrites;
		++countLogicalWrites;
		//Standalone<StringRef> copy = StringRef((const uint8_t*)data, length);
		return write_impl( fd, err, StringRef((const uint8_t*)data, length), offset );
	}
	virtual Future<Void> truncate( int64_t size ) {
		++countFileLogicalWrites;
		++countLogicalWrites;
		return truncate_impl( fd, err, size );
	}
	virtual Future<Void> sync() {
		++countFileLogicalWrites;
		++countLogicalWrites;
		auto fsync = sync_impl( fd, err );

		if (flags & OPEN_ATOMIC_WRITE_AND_CREATE){
			flags &= ~OPEN_ATOMIC_WRITE_AND_CREATE;

			return waitAndAtomicRename( fsync, filename+".part", filename );
		}

		return fsync;
	}
	virtual Future<int64_t> size() {
		++countFileLogicalReads;
		++countLogicalReads;
				
		struct stat buf;
		if (fstat( fd, &buf )) {
			TraceEvent("AsyncFileEIOFStatError").detail("fd",fd).GetLastError();
			return io_error();
		}
		return buf.st_size;
		
		//return size_impl(fd);
	}
	virtual std::string getFilename() {
		return filename;
	}

	ACTOR static Future<Void> async_fsync_parent( std::string filename ) {
		std::string folder = parentDirectory( filename );
		TraceEvent("FSyncParentDir").detail("Folder", folder).detail("File", filename);
		state int folderFD = ::open( folder.c_str(), O_DIRECTORY, 0 );
		if (folderFD<0)
			throw io_error();
		try {
			Void _ = wait( async_fsync(folderFD) ); // not sure if fdatasync on the folder has the same effect
		} catch (...) {
			close(folderFD);
			throw;
		}
		close(folderFD);
		return Void();
	}

	static Future<Void> async_fdatasync( int fd ) {
		// Used by AsyncFileKAIO, since kernel AIO doesn't really implement fdatasync yet
		return sync_impl( fd, Reference<ErrorInfo>(new ErrorInfo) );
	}
	static Future<Void> async_fsync( int fd ) {
		// Used by AsyncFileKAIO, since kernel AIO doesn't really implement fsync yet
		return sync_impl( fd, Reference<ErrorInfo>(new ErrorInfo), true );
	}
	ACTOR static Future<Void> waitAndAtomicRename( Future<Void> fsync, std::string part_filename, std::string final_filename ) {
		// First wait for the data in the part file to be durable
		Void _ = wait(fsync);

		// rename() is atomic
		if (rename( part_filename.c_str(), final_filename.c_str() )) {
			TraceEvent("AsyncFileEIORenameError").detail("filename", final_filename).GetLastError();
			throw io_error();
		}

		// fsync the parent directory to make it durable as well
		Void _ = wait( async_fsync_parent(final_filename) );

		return Void();
	}

	// Run the given function on the EIO thread pool and return its result
	template <class R> static Future<R> dispatch( std::function<R()> const& func ) {
		return dispatch_impl(func);
	}

	~AsyncFileEIO() { close_impl( fd ); }

private:
	struct ErrorInfo : ReferenceCounted<ErrorInfo>, FastAllocated<ErrorInfo> {
		Error err;
		void set( const Error& e ) {
			if (err.code() == invalid_error_code)
				err = e;
		}
		void report() {
			if (err.code() != invalid_error_code) 
				throw err;
		}
	};

	template <class R>
	struct Dispatch {
		std::function<R()> func;
		ErrorOr<R> result;
		Promise<Void> done;
		explicit Dispatch( std::function<R()> const& func ) : func(func) {}
	};

	int fd, flags;
	Reference<ErrorInfo> err;
	std::string filename;
	Int64MetricHandle countFileLogicalWrites;
	Int64MetricHandle countFileLogicalReads;

	Int64MetricHandle countLogicalWrites;
	Int64MetricHandle countLogicalReads;

	AsyncFileEIO( int fd, int flags, std::string const& filename ) : fd(fd), flags(flags), filename(filename), err(new ErrorInfo) {
		if( !g_network->isSimulated() ) {
			countFileLogicalWrites.init(LiteralStringRef("AsyncFile.CountFileLogicalWrites"), filename);
			countFileLogicalReads.init( LiteralStringRef("AsyncFile.CountFileLogicalReads"), filename);

			countLogicalWrites.init(LiteralStringRef("AsyncFile.CountLogicalWrites"));
			countLogicalReads.init( LiteralStringRef("AsyncFile.CountLogicalReads"));
		}
	}

	static int openFlags(int flags) {
		int oflags = 0;
		ASSERT( bool(flags & OPEN_READONLY) != bool(flags & OPEN_READWRITE) );  // readonly xor readwrite
		if( flags & OPEN_EXCLUSIVE ) oflags |= O_EXCL;
		if( flags & OPEN_CREATE )    oflags |= O_CREAT;
		if( flags & OPEN_READONLY )  oflags |= O_RDONLY;
		if( flags & OPEN_READWRITE ) oflags |= O_RDWR;
		if( flags & OPEN_ATOMIC_WRITE_AND_CREATE ) oflags |= O_TRUNC;
		return oflags;
	}

	static void error( const char* context, int fd, eio_req* r, Reference<ErrorInfo> const& err = Reference<ErrorInfo>() ) {
		Error e = io_error();
		errno = r->errorno;
		TraceEvent(context).detail("fd", fd).detail("Result", r->result).GetLastError().error(e);
		if (err) err->set(e);
		else throw e;
	}

	ACTOR static void close_impl( int fd ) {
		state Promise<Void> p;
		state eio_req* r = eio_close(fd, 0, eio_callback, &p);
		Void _ = wait( p.getFuture() );
		if (r->result) error( "CloseError", fd, r );
		TraceEvent("AsyncFileClosed").detail("fd", fd).suppressFor(1.0);
	}

	ACTOR static Future<int> read_impl( int fd, void* data, int length, int64_t offset ) {
		state int taskID = g_network->getCurrentTask();
		state Promise<Void> p;
		//fprintf(stderr, "eio_read (fd=%d length=%d offset=%lld)\n", fd, length, offset);
		state eio_req* r = eio_read(fd, data, length, offset, 0, eio_callback, &p);
		try { Void _ = wait( p.getFuture() ); } catch (...) { g_network->setCurrentTask( taskID ); eio_cancel(r); throw; }
		try {
			state int result = r->result;
			//printf("eio read: %d/%d\n", r->result, length);
			if (result == -1) {
				error("ReadError", fd, r);
				throw internal_error();
			} else {
				Void _ = wait( delay(0, taskID) );
				return result;
			}
		} catch( Error &_e ) {
			state Error e = _e;
			Void _ = wait( delay(0, taskID) );
			throw e;
		}
	}

	ACTOR static Future<Void> write_impl( int fd, Reference<ErrorInfo> err, StringRef data, int64_t offset ) {
		state int taskID = g_network->getCurrentTask();
		state Promise<Void> p;
		state eio_req* r = eio_write(fd, (void*)data.begin(), data.size(), offset, 0, eio_callback, &p);
		try { Void _ = wait( p.getFuture() ); } catch (...) { g_network->setCurrentTask( taskID ); eio_cancel(r); throw; }
		if (r->result != data.size()) error("WriteError", fd, r, err);
		Void _ = wait( delay(0, taskID) );
		return Void();
	}

	ACTOR static Future<Void> truncate_impl( int fd, Reference<ErrorInfo> err, int64_t size ) {
		state int taskID = g_network->getCurrentTask();
		state Promise<Void> p;
		state eio_req* r = eio_ftruncate(fd, size, 0, eio_callback, &p);
		try { Void _ = wait( p.getFuture() ); } catch (...) { g_network->setCurrentTask( taskID ); eio_cancel(r); throw; }
		if (r->result) error("TruncateError", fd, r, err);
		Void _ = wait( delay(0, taskID) );
		return Void();
	}

	static eio_req* start_fsync( int fd, Promise<Void>& p, bool sync_metadata ) {
		#ifdef __APPLE__
			// Neither fsync() nor fdatasync() do the right thing on OS X!
			eio_req *req = (eio_req *)calloc (1, sizeof *req);
			req->type = EIO_CUSTOM;
			req->pri = 0;
			req->finish = eio_callback;
			req->data = &p;
			req->destroy = free_req;
			req->int1 = fd;
			req->feed = apple_fsync;
			eio_submit( req );
			return req;
		#else
			if (sync_metadata)
				return eio_fsync( fd, 0, eio_callback, &p );
			else
				return eio_fdatasync( fd, 0, eio_callback, &p );
		#endif
	}

	ACTOR static Future<Void> sync_impl( int fd, Reference<ErrorInfo> err, bool sync_metadata=false ) {
		state int taskID = g_network->getCurrentTask();
		state Promise<Void> p;
		state eio_req* r = start_fsync( fd, p, sync_metadata );
		
		try { Void _ = wait( p.getFuture() ); } catch (...) { g_network->setCurrentTask( taskID ); eio_cancel(r); throw; }
		try {
			// Report any errors from prior write() or truncate() calls
			err->report();

			if (r->result) error("SyncError", fd, r);
			Void _ = wait( delay(0, taskID) );
			return Void();
		} catch( Error &_e ) {
			state Error e = _e;
			Void _ = wait( delay(0, taskID) );
			throw e;
		}
	}

	ACTOR static Future<int64_t> size_impl( int fd ) {
		state int taskID = g_network->getCurrentTask();
		state Promise<Void> p;
		state eio_req* r = eio_fstat( fd, 0, eio_callback, &p );
		try { Void _ = wait( p.getFuture() ); } catch (...) { g_network->setCurrentTask( taskID ); eio_cancel(r); throw; }
		if (r->result) error("StatError", fd, r);
		EIO_STRUCT_STAT *statdata = (EIO_STRUCT_STAT *)r->ptr2;
		if (!statdata) error("StatBufferError", fd, r);
		state int64_t size = statdata->st_size;
		free(statdata);
		Void _ = wait( delay(0, taskID) );
		return size;
	}

	ACTOR template <class R> static Future<R> dispatch_impl( std::function<R()> func) {
		state Dispatch<R> data( func );
		state int taskID = g_network->getCurrentTask();

		state eio_req* r = eio_custom( [](eio_req* req) {
			// Runs on the eio thread pool
			auto data = reinterpret_cast<Dispatch<R>*>(req->data);
			try {
				data->result = data->func();
				req->result = 0;
			} catch (Error& e) {
				data->result = e;
				req->result = -1;
			} catch (...) {
				data->result = unknown_error();
				req->result = -1;
			}
		}, 0, [](eio_req* req) {
			// Runs on the main thread, in eio_poll()
			if (EIO_CANCELLED (req)) return 0;
			auto data = reinterpret_cast<Dispatch<R>*>(req->data);
			Promise<Void> p = std::move( data->done );
			p.send(Void());
			return 0;
		}, &data);
		try { Void _ = wait( data.done.getFuture() ); } catch (...) { g_network->setCurrentTask( taskID ); eio_cancel(r); throw; }

		Void _ = wait( delay(0, taskID) );
		if (data.result.isError()) throw data.result.getError();
		return data.result.get();
	}

	static volatile int32_t want_poll;

	ACTOR static void poll_eio() {
		while (eio_poll() == -1)
			Void _ = wait( yield() );
		want_poll = 0;
	}

	static void eio_want_poll() {
		want_poll = 1;
		// SOMEDAY: NULL for deferred error, no analysis of correctness (itp)
		onMainThreadVoid([](){ poll_eio(); }, NULL, TaskPollEIO);
	}

	static int eio_callback( eio_req* req ) {
		if (EIO_CANCELLED (req)) return 0;
		Promise<Void> p = std::move( *(Promise<Void>*)req->data );
		p.send(Void());
		return 0;
	}

	#ifdef __APPLE__
	static void apple_fsync( eio_req* req ) {
		req->result = fcntl(req->int1, F_FULLFSYNC, 0);
	}
	static void free_req( eio_req* req ) { free(req); }
	#endif
};

#ifdef FILESYSTEM_IMPL
volatile int32_t AsyncFileEIO::want_poll = 0;
#endif

#endif 
#endif