bitcoin: src/leveldb/util/env_posix.cc comparison

comparison src/leveldb/util/env_posix.cc @ 3634:98b459278ba3 draft

Import LevelDB 1.5, it will be used for the transaction database.

author	Mike Hearn <hearn@google.com>
date	Mon, 25 Jun 2012 11:17:22 +0200
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-:94f6e3e0c600
+:98b459278ba3
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+#include <deque>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <time.h>
+#include <unistd.h>
+#if defined(LEVELDB_PLATFORM_ANDROID)
+#include <sys/stat.h>
+#endif
+#include "leveldb/env.h"
+#include "leveldb/slice.h"
+#include "port/port.h"
+#include "util/logging.h"
+#include "util/posix_logger.h"
+namespace leveldb {
+namespace {
+static Status IOError(const std::string& context, int err_number) {
+return Status::IOError(context, strerror(err_number));
+}
+class PosixSequentialFile: public SequentialFile {
+private:
+std::string filename_;
+FILE* file_;
+public:
+PosixSequentialFile(const std::string& fname, FILE* f)
+: filename_(fname), file_(f) { }
+virtual ~PosixSequentialFile() { fclose(file_); }
+virtual Status Read(size_t n, Slice* result, char* scratch) {
+Status s;
+size_t r = fread_unlocked(scratch, 1, n, file_);
+*result = Slice(scratch, r);
+if (r < n) {
+if (feof(file_)) {
+// We leave status as ok if we hit the end of the file
+} else {
+// A partial read with an error: return a non-ok status
+s = IOError(filename_, errno);
+}
+}
+return s;
+}
+virtual Status Skip(uint64_t n) {
+if (fseek(file_, n, SEEK_CUR)) {
+return IOError(filename_, errno);
+}
+return Status::OK();
+}
+};
+// pread() based random-access
+class PosixRandomAccessFile: public RandomAccessFile {
+private:
+std::string filename_;
+int fd_;
+public:
+PosixRandomAccessFile(const std::string& fname, int fd)
+: filename_(fname), fd_(fd) { }
+virtual ~PosixRandomAccessFile() { close(fd_); }
+virtual Status Read(uint64_t offset, size_t n, Slice* result,
+char* scratch) const {
+Status s;
+ssize_t r = pread(fd_, scratch, n, static_cast<off_t>(offset));
+*result = Slice(scratch, (r < 0) ? 0 : r);
+if (r < 0) {
+// An error: return a non-ok status
+s = IOError(filename_, errno);
+}
+return s;
+}
+};
+// mmap() based random-access
+class PosixMmapReadableFile: public RandomAccessFile {
+private:
+std::string filename_;
+void* mmapped_region_;
+size_t length_;
+public:
+// base[0,length-1] contains the mmapped contents of the file.
+PosixMmapReadableFile(const std::string& fname, void* base, size_t length)
+: filename_(fname), mmapped_region_(base), length_(length) { }
+virtual ~PosixMmapReadableFile() { munmap(mmapped_region_, length_); }
+virtual Status Read(uint64_t offset, size_t n, Slice* result,
+char* scratch) const {
+Status s;
+if (offset + n > length_) {
+*result = Slice();
+s = IOError(filename_, EINVAL);
+} else {
+*result = Slice(reinterpret_cast<char*>(mmapped_region_) + offset, n);
+}
+return s;
+}
+};
+// We preallocate up to an extra megabyte and use memcpy to append new
+// data to the file.  This is safe since we either properly close the
+// file before reading from it, or for log files, the reading code
+// knows enough to skip zero suffixes.
+class PosixMmapFile : public WritableFile {
+private:
+std::string filename_;
+int fd_;
+size_t page_size_;
+size_t map_size_;       // How much extra memory to map at a time
+char* base_;            // The mapped region
+char* limit_;           // Limit of the mapped region
+char* dst_;             // Where to write next  (in range [base_,limit_])
+char* last_sync_;       // Where have we synced up to
+uint64_t file_offset_;  // Offset of base_ in file
+// Have we done an munmap of unsynced data?
+bool pending_sync_;
+// Roundup x to a multiple of y
+static size_t Roundup(size_t x, size_t y) {
+return ((x + y - 1) / y) * y;
+}
+size_t TruncateToPageBoundary(size_t s) {
+s -= (s & (page_size_ - 1));
+assert((s % page_size_) == 0);
+return s;
+}
+bool UnmapCurrentRegion() {
+bool result = true;
+if (base_ != NULL) {
+if (last_sync_ < limit_) {
+// Defer syncing this data until next Sync() call, if any
+pending_sync_ = true;
+}
+if (munmap(base_, limit_ - base_) != 0) {
+result = false;
+}
+file_offset_ += limit_ - base_;
+base_ = NULL;
+limit_ = NULL;
+last_sync_ = NULL;
+dst_ = NULL;
+// Increase the amount we map the next time, but capped at 1MB
+if (map_size_ < (1<<20)) {
+map_size_ *= 2;
+}
+}
+return result;
+}
+bool MapNewRegion() {
+assert(base_ == NULL);
+if (ftruncate(fd_, file_offset_ + map_size_) < 0) {
+return false;
+}
+void* ptr = mmap(NULL, map_size_, PROT_READ | PROT_WRITE, MAP_SHARED,
+fd_, file_offset_);
+if (ptr == MAP_FAILED) {
+return false;
+}
+base_ = reinterpret_cast<char*>(ptr);
+limit_ = base_ + map_size_;
+dst_ = base_;
+last_sync_ = base_;
+return true;
+}
+public:
+PosixMmapFile(const std::string& fname, int fd, size_t page_size)
+: filename_(fname),
+fd_(fd),
+page_size_(page_size),
+map_size_(Roundup(65536, page_size)),
+base_(NULL),
+limit_(NULL),
+dst_(NULL),
+last_sync_(NULL),
+file_offset_(0),
+pending_sync_(false) {
+assert((page_size & (page_size - 1)) == 0);
+}
+~PosixMmapFile() {
+if (fd_ >= 0) {
+PosixMmapFile::Close();
+}
+}
+virtual Status Append(const Slice& data) {
+const char* src = data.data();
+size_t left = data.size();
+while (left > 0) {
+assert(base_ <= dst_);
+assert(dst_ <= limit_);
+size_t avail = limit_ - dst_;
+if (avail == 0) {
+if (!UnmapCurrentRegion() ||
+!MapNewRegion()) {
+return IOError(filename_, errno);
+}
+}
+size_t n = (left <= avail) ? left : avail;
+memcpy(dst_, src, n);
+dst_ += n;
+src += n;
+left -= n;
+}
+return Status::OK();
+}
+virtual Status Close() {
+Status s;
+size_t unused = limit_ - dst_;
+if (!UnmapCurrentRegion()) {
+s = IOError(filename_, errno);
+} else if (unused > 0) {
+// Trim the extra space at the end of the file
+if (ftruncate(fd_, file_offset_ - unused) < 0) {
+s = IOError(filename_, errno);
+}
+}
+if (close(fd_) < 0) {
+if (s.ok()) {
+s = IOError(filename_, errno);
+}
+}
+fd_ = -1;
+base_ = NULL;
+limit_ = NULL;
+return s;
+}
+virtual Status Flush() {
+return Status::OK();
+}
+virtual Status Sync() {
+Status s;
+if (pending_sync_) {
+// Some unmapped data was not synced
+pending_sync_ = false;
+if (fdatasync(fd_) < 0) {
+s = IOError(filename_, errno);
+}
+}
+if (dst_ > last_sync_) {
+// Find the beginnings of the pages that contain the first and last
+// bytes to be synced.
+size_t p1 = TruncateToPageBoundary(last_sync_ - base_);
+size_t p2 = TruncateToPageBoundary(dst_ - base_ - 1);
+last_sync_ = dst_;
+if (msync(base_ + p1, p2 - p1 + page_size_, MS_SYNC) < 0) {
+s = IOError(filename_, errno);
+}
+}
+return s;
+}
+};
+static int LockOrUnlock(int fd, bool lock) {
+errno = 0;
+struct flock f;
+memset(&f, 0, sizeof(f));
+f.l_type = (lock ? F_WRLCK : F_UNLCK);
+f.l_whence = SEEK_SET;
+f.l_start = 0;
+f.l_len = 0;        // Lock/unlock entire file
+return fcntl(fd, F_SETLK, &f);
+}
+class PosixFileLock : public FileLock {
+public:
+int fd_;
+};
+class PosixEnv : public Env {
+public:
+PosixEnv();
+virtual ~PosixEnv() {
+fprintf(stderr, "Destroying Env::Default()\n");
+exit(1);
+}
+virtual Status NewSequentialFile(const std::string& fname,
+SequentialFile** result) {
+FILE* f = fopen(fname.c_str(), "r");
+if (f == NULL) {
+*result = NULL;
+return IOError(fname, errno);
+} else {
+*result = new PosixSequentialFile(fname, f);
+return Status::OK();
+}
+}
+virtual Status NewRandomAccessFile(const std::string& fname,
+RandomAccessFile** result) {
+*result = NULL;
+Status s;
+int fd = open(fname.c_str(), O_RDONLY);
+if (fd < 0) {
+s = IOError(fname, errno);
+} else if (sizeof(void*) >= 8) {
+// Use mmap when virtual address-space is plentiful.
+uint64_t size;
+s = GetFileSize(fname, &size);
+if (s.ok()) {
+void* base = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0);
+if (base != MAP_FAILED) {
+*result = new PosixMmapReadableFile(fname, base, size);
+} else {
+s = IOError(fname, errno);
+}
+}
+close(fd);
+} else {
+*result = new PosixRandomAccessFile(fname, fd);
+}
+return s;
+}
+virtual Status NewWritableFile(const std::string& fname,
+WritableFile** result) {
+Status s;
+const int fd = open(fname.c_str(), O_CREAT | O_RDWR | O_TRUNC, 0644);
+if (fd < 0) {
+*result = NULL;
+s = IOError(fname, errno);
+} else {
+*result = new PosixMmapFile(fname, fd, page_size_);
+}
+return s;
+}
+virtual bool FileExists(const std::string& fname) {
+return access(fname.c_str(), F_OK) == 0;
+}
+virtual Status GetChildren(const std::string& dir,
+std::vector<std::string>* result) {
+result->clear();
+DIR* d = opendir(dir.c_str());
+if (d == NULL) {
+return IOError(dir, errno);
+}
+struct dirent* entry;
+while ((entry = readdir(d)) != NULL) {
+result->push_back(entry->d_name);
+}
+closedir(d);
+return Status::OK();
+}
+virtual Status DeleteFile(const std::string& fname) {
+Status result;
+if (unlink(fname.c_str()) != 0) {
+result = IOError(fname, errno);
+}
+return result;
+};
+virtual Status CreateDir(const std::string& name) {
+Status result;
+if (mkdir(name.c_str(), 0755) != 0) {
+result = IOError(name, errno);
+}
+return result;
+};
+virtual Status DeleteDir(const std::string& name) {
+Status result;
+if (rmdir(name.c_str()) != 0) {
+result = IOError(name, errno);
+}
+return result;
+};
+virtual Status GetFileSize(const std::string& fname, uint64_t* size) {
+Status s;
+struct stat sbuf;
+if (stat(fname.c_str(), &sbuf) != 0) {
+*size = 0;
+s = IOError(fname, errno);
+} else {
+*size = sbuf.st_size;
+}
+return s;
+}
+virtual Status RenameFile(const std::string& src, const std::string& target) {
+Status result;
+if (rename(src.c_str(), target.c_str()) != 0) {
+result = IOError(src, errno);
+}
+return result;
+}
+virtual Status LockFile(const std::string& fname, FileLock** lock) {
+*lock = NULL;
+Status result;
+int fd = open(fname.c_str(), O_RDWR | O_CREAT, 0644);
+if (fd < 0) {
+result = IOError(fname, errno);
+} else if (LockOrUnlock(fd, true) == -1) {
+result = IOError("lock " + fname, errno);
+close(fd);
+} else {
+PosixFileLock* my_lock = new PosixFileLock;
+my_lock->fd_ = fd;
+*lock = my_lock;
+}
+return result;
+}
+virtual Status UnlockFile(FileLock* lock) {
+PosixFileLock* my_lock = reinterpret_cast<PosixFileLock*>(lock);
+Status result;
+if (LockOrUnlock(my_lock->fd_, false) == -1) {
+result = IOError("unlock", errno);
+}
+close(my_lock->fd_);
+delete my_lock;
+return result;
+}
+virtual void Schedule(void (*function)(void*), void* arg);
+virtual void StartThread(void (*function)(void* arg), void* arg);
+virtual Status GetTestDirectory(std::string* result) {
+const char* env = getenv("TEST_TMPDIR");
+if (env && env[0] != '\0') {
+*result = env;
+} else {
+char buf[100];
+snprintf(buf, sizeof(buf), "/tmp/leveldbtest-%d", int(geteuid()));
+*result = buf;
+}
+// Directory may already exist
+CreateDir(*result);
+return Status::OK();
+}
+static uint64_t gettid() {
+pthread_t tid = pthread_self();
+uint64_t thread_id = 0;
+memcpy(&thread_id, &tid, std::min(sizeof(thread_id), sizeof(tid)));
+return thread_id;
+}
+virtual Status NewLogger(const std::string& fname, Logger** result) {
+FILE* f = fopen(fname.c_str(), "w");
+if (f == NULL) {
+*result = NULL;
+return IOError(fname, errno);
+} else {
+*result = new PosixLogger(f, &PosixEnv::gettid);
+return Status::OK();
+}
+}
+virtual uint64_t NowMicros() {
+struct timeval tv;
+gettimeofday(&tv, NULL);
+return static_cast<uint64_t>(tv.tv_sec) * 1000000 + tv.tv_usec;
+}
+virtual void SleepForMicroseconds(int micros) {
+usleep(micros);
+}
+private:
+void PthreadCall(const char* label, int result) {
+if (result != 0) {
+fprintf(stderr, "pthread %s: %s\n", label, strerror(result));
+exit(1);
+}
+}
+// BGThread() is the body of the background thread
+void BGThread();
+static void* BGThreadWrapper(void* arg) {
+reinterpret_cast<PosixEnv*>(arg)->BGThread();
+return NULL;
+}
+size_t page_size_;
+pthread_mutex_t mu_;
+pthread_cond_t bgsignal_;
+pthread_t bgthread_;
+bool started_bgthread_;
+// Entry per Schedule() call
+struct BGItem { void* arg; void (*function)(void*); };
+typedef std::deque<BGItem> BGQueue;
+BGQueue queue_;
+};
+PosixEnv::PosixEnv() : page_size_(getpagesize()),
+started_bgthread_(false) {
+PthreadCall("mutex_init", pthread_mutex_init(&mu_, NULL));
+PthreadCall("cvar_init", pthread_cond_init(&bgsignal_, NULL));
+}
+void PosixEnv::Schedule(void (*function)(void*), void* arg) {
+PthreadCall("lock", pthread_mutex_lock(&mu_));
+// Start background thread if necessary
+if (!started_bgthread_) {
+started_bgthread_ = true;
+PthreadCall(
+"create thread",
+pthread_create(&bgthread_, NULL,  &PosixEnv::BGThreadWrapper, this));
+}
+// If the queue is currently empty, the background thread may currently be
+// waiting.
+if (queue_.empty()) {
+PthreadCall("signal", pthread_cond_signal(&bgsignal_));
+}
+// Add to priority queue
+queue_.push_back(BGItem());
+queue_.back().function = function;
+queue_.back().arg = arg;
+PthreadCall("unlock", pthread_mutex_unlock(&mu_));
+}
+void PosixEnv::BGThread() {
+while (true) {
+// Wait until there is an item that is ready to run
+PthreadCall("lock", pthread_mutex_lock(&mu_));
+while (queue_.empty()) {
+PthreadCall("wait", pthread_cond_wait(&bgsignal_, &mu_));
+}
+void (*function)(void*) = queue_.front().function;
+void* arg = queue_.front().arg;
+queue_.pop_front();
+PthreadCall("unlock", pthread_mutex_unlock(&mu_));
+(*function)(arg);
+}
+}
+namespace {
+struct StartThreadState {
+void (*user_function)(void*);
+void* arg;
+};
+}
+static void* StartThreadWrapper(void* arg) {
+StartThreadState* state = reinterpret_cast<StartThreadState*>(arg);
+state->user_function(state->arg);
+delete state;
+return NULL;
+}
+void PosixEnv::StartThread(void (*function)(void* arg), void* arg) {
+pthread_t t;
+StartThreadState* state = new StartThreadState;
+state->user_function = function;
+state->arg = arg;
+PthreadCall("start thread",
+pthread_create(&t, NULL,  &StartThreadWrapper, state));
+}
+}  // namespace
+static pthread_once_t once = PTHREAD_ONCE_INIT;
+static Env* default_env;
+static void InitDefaultEnv() { default_env = new PosixEnv; }
+Env* Env::Default() {
+pthread_once(&once, InitDefaultEnv);
+return default_env;
+}
+}  // namespace leveldb

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comparison src/leveldb/util/env_posix.cc @ 3634:98b459278ba3 draft