win: Add open equivalent

util/file/file_writer.cc

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // 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.
 
 #include "util/file/file_writer.h"
 
 #include <algorithm>
 
 #include <limits.h>
 
 #include "base/logging.h"
-#include "base/posix/eintr_wrapper.h"
 #include "util/file/file_io.h"
 
 namespace crashpad {
 
-// Ensure type compatibility between WritableIoVec and iovec.
-static_assert(sizeof(WritableIoVec) == sizeof(iovec), "WritableIoVec size");
-static_assert(offsetof(WritableIoVec, iov_base) == offsetof(iovec, iov_base),
-              "WritableIoVec base offset");
-static_assert(offsetof(WritableIoVec, iov_len) == offsetof(iovec, iov_len),
-              "WritableIoVec len offset");
-
-FileWriter::FileWriter() : fd_() {
+FileWriter::FileWriter() : file_() {
 }
 
 FileWriter::~FileWriter() {
 }
 
-bool FileWriter::Open(const base::FilePath& path, int oflag, mode_t mode) {
-  CHECK(!fd_.is_valid());
+void FileWriter::Close() {
+  CHECK(file_.is_valid());
 
-  DCHECK((oflag & O_WRONLY) || (oflag & O_RDWR));
-
-  fd_.reset(HANDLE_EINTR(open(path.value().c_str(), oflag, mode)));
-  if (!fd_.is_valid()) {
-    PLOG(ERROR) << "open " << path.value();
-    return false;
-  }
-
-  return true;
-}
-
-void FileWriter::Close() {
-  CHECK(fd_.is_valid());
-
-  fd_.reset();
+  file_.reset();
 }
 
 bool FileWriter::Write(const void* data, size_t size) {
-  DCHECK(fd_.is_valid());
+  DCHECK(file_.is_valid());
 
   // TODO(mark): Write no more than SSIZE_MAX bytes in a single call.
-  ssize_t written = WriteFile(fd_.get(), data, size);
+  ssize_t written = WriteFile(file_.get(), data, size);
   if (written < 0) {
     PLOG(ERROR) << "write";
     return false;
   } else if (written == 0) {
     LOG(ERROR) << "write: returned 0";
     return false;
   }
 
   return true;
 }
 
-bool FileWriter::WriteIoVec(std::vector<WritableIoVec>* iovecs) {
-  DCHECK(fd_.is_valid());
-
-  ssize_t size = 0;
-  for (const WritableIoVec& iov : *iovecs) {
-    // TODO(mark): Check to avoid overflow of ssize_t, and fail with EINVAL.
-    size += iov.iov_len;
-  }
-
-  // Get an iovec*, because that’s what writev wants. The only difference
-  // between WritableIoVec and iovec is that WritableIoVec’s iov_base is a
-  // pointer to a const buffer, where iovec’s iov_base isn’t. writev doesn’t
-  // actually write to the data, so this cast is safe here. iovec’s iov_base is
-  // non-const because the same structure is used for readv and writev, and
-  // readv needs to write to the buffer that iov_base points to.
-  iovec* iov = reinterpret_cast<iovec*>(&(*iovecs)[0]);
-  size_t remaining_iovecs = iovecs->size();
-
-  while (size > 0) {
-    size_t writev_iovec_count =
-        std::min(remaining_iovecs, implicit_cast<size_t>(IOV_MAX));
-    ssize_t written = HANDLE_EINTR(writev(fd_.get(), iov, writev_iovec_count));
-    if (written < 0) {
-      PLOG(ERROR) << "writev";
-      return false;
-    } else if (written == 0) {
-      LOG(ERROR) << "writev: returned 0";
-      return false;
-    }
-
-    size -= written;
-    DCHECK_GE(size, 0);
-
-    if (size == 0) {
-      remaining_iovecs = 0;
-      break;
-    }
-
-    while (written > 0) {
-      size_t wrote_this_iovec =
-          std::min(implicit_cast<size_t>(written), iov->iov_len);
-      written -= wrote_this_iovec;
-      if (wrote_this_iovec < iov->iov_len) {
-        iov->iov_base =
-            reinterpret_cast<char*>(iov->iov_base) + wrote_this_iovec;
-        iov->iov_len -= wrote_this_iovec;
-      } else {
-        ++iov;
-        --remaining_iovecs;
-      }
-    }
-  }
-
-  DCHECK_EQ(remaining_iovecs, 0u);
-
-#ifndef NDEBUG
-  // The interface says that |iovecs| is not sacred, so scramble it to make sure
-  // that nobody depends on it.
-  memset(&(*iovecs)[0], 0xa5, sizeof((*iovecs)[0]) * iovecs->size());
-#endif
-
-  return true;
-}
-
-off_t FileWriter::Seek(off_t offset, int whence) {
-  DCHECK(fd_.is_valid());
-
-  off_t rv = lseek(fd_.get(), offset, whence);
-  if (rv < 0) {
-    PLOG(ERROR) << "lseek";
-  }
-
-  return rv;
-}
-
 }  // namespace crashpad