crashpad_database_util: Accept --new-report=- to read a new report from standard input

util/file/file_reader.cc

 // Copyright 2015 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_reader.h"
 
 #include "base/logging.h"
 #include "base/numerics/safe_conversions.h"
+#include "build/build_config.h"
 
 namespace crashpad {
 
 bool FileReaderInterface::ReadExactly(void* data, size_t size) {
   ssize_t expect = base::checked_cast<ssize_t>(size);
   ssize_t rv = Read(data, size);
   if (rv < 0) {
     // Read() will have logged its own error.
     return false;
   } else if (rv != expect) {
@@ skipping 61 matching lines @@
 ssize_t FileReader::Read(void* data, size_t size) {
   DCHECK(file_.is_valid());
   return weak_file_handle_file_reader_.Read(data, size);
 }
 
 FileOffset FileReader::Seek(FileOffset offset, int whence) {
   DCHECK(file_.is_valid());
   return weak_file_handle_file_reader_.Seek(offset, whence);
 }
 
+WeakStdioFileReader::WeakStdioFileReader(FILE* file)
+    : file_(file) {
+}
+
+WeakStdioFileReader::~WeakStdioFileReader() {
+}
+
+ssize_t WeakStdioFileReader::Read(void* data, size_t size) {
+  DCHECK(file_);
+
+  size_t rv = fread(data, 1, size, file_);
+  if (rv < size && ferror(file_)) {
+    STDIO_PLOG(ERROR) << "fread";
+    return -1;
+  }
+
+  return rv;
+}
+
+FileOffset WeakStdioFileReader::Seek(FileOffset offset, int whence) {
+  DCHECK(file_);
+  if (fseeko(file_, offset, whence) == -1) {
+    STDIO_PLOG(ERROR) << "fseeko";
+    return -1;
+  }
+
+  FileOffset new_offset = ftello(file_);
+  if (new_offset == -1) {
+    STDIO_PLOG(ERROR) << "ftello";
+    return -1;
+  }
+
+  return new_offset;
+}
+
 }  // namespace crashpad