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

util/file/file_reader.h

Index: util/file/file_reader.h
diff --git a/util/file/file_reader.h b/util/file/file_reader.h
index 0c6856f1a804913ea0835a86956379030ca510c9..58f58651ad10cb5ffb8c51e06e5b5d5309b22d41 100644
--- a/util/file/file_reader.h
+++ b/util/file/file_reader.h
@@ -15,6 +15,7 @@
 #ifndef CRASHPAD_UTIL_FILE_FILE_READER_H_
 #define CRASHPAD_UTIL_FILE_FILE_READER_H_
 
+#include <stdio.h>
 #include <sys/types.h>
 
 #include "base/basictypes.h"
@@ -28,6 +29,8 @@ namespace crashpad {
 //!     semantics matching the underlying platform (POSIX or Windows).
 class FileReaderInterface : public virtual FileSeekerInterface {
  public:
+  virtual ~FileReaderInterface() {}
+
   //! \brief Wraps ReadFile(), or provides an implementation with identical
   //!     semantics.
   //!
@@ -44,9 +47,6 @@ class FileReaderInterface : public virtual FileSeekerInterface {
   //! \return `true` if the operation succeeded, `false` if it failed, with an
   //!     error message logged. Short reads are treated as failures.
   bool ReadExactly(void* data, size_t size);
-
- protected:
-  ~FileReaderInterface() {}
 };
 
 //! \brief A file reader backed by a FileHandle.
@@ -66,7 +66,7 @@ class FileReaderInterface : public virtual FileSeekerInterface {
 class WeakFileHandleFileReader : public FileReaderInterface {
  public:
   explicit WeakFileHandleFileReader(FileHandle file_handle);
-  ~WeakFileHandleFileReader();
+  ~WeakFileHandleFileReader() override;
 
   // FileReaderInterface:
   ssize_t Read(void* data, size_t size) override;
@@ -99,7 +99,7 @@ class WeakFileHandleFileReader : public FileReaderInterface {
 class FileReader : public FileReaderInterface {
  public:
   FileReader();
-  ~FileReader();
+  ~FileReader() override;
 
   // FileReaderInterface:
 
@@ -142,6 +142,40 @@ class FileReader : public FileReaderInterface {
   DISALLOW_COPY_AND_ASSIGN(FileReader);
 };
 
+//! \brief A file reader backed by a standard input/output `FILE*`.
+//!
+//! This class accepts an already-open `FILE*`. It is not responsible for
+//! opening or closing this `FILE*`. Users of this class must ensure that the
+//! `FILE*` is closed appropriately elsewhere. Objects of this class may be used
+//! to read from `FILE*` objects not associated with filesystem-based files,
+//! although special attention should be paid to the Seek() method, which may
+//! not function on `FILE*` objects that do not refer to disk-based files.
+//!
+//! This class is expected to be used when other code is responsible for
+//! opening `FILE*` objects and already provides `FILE*` objects. A good use
+//! would be a WeakStdioFileReader for `stdin`.
+class WeakStdioFileReader : public FileReaderInterface {

[Robert Sesek, 2015/04/23 13:40:13]

Why use this instead of WeakFileHandleReader(STDIN_FILENO) ? 

[Mark Mentovai, 2015/08/06 14:30:08]

Robert Sesek wrote:
I did try WeakFileHandleReader(fileno(stdin)) first, but it didn’t work as well.
It totally misses the EOF when stdin is a terminal:

mark@mela zsh% out/Debug/crashpad_database_util -d /tmp/z --new-report=-  
crash report
^D
[…wait…]

It only hears it when you press ^D twice in a row. Weird. The loop in ReadFile()
gets the whole string on the first attempt, but then goes back to block even
though the ^D should have closed it and the next read should immediately return
0.

+ public:
+  explicit WeakStdioFileReader(FILE* file);
+  ~WeakStdioFileReader() override;
+
+  // FileReaderInterface:
+  ssize_t Read(void* data, size_t size) override;
+
+  // FileSeekerInterface:
+
+  //! \copydoc FileReaderInterface::Seek()
+  //!
+  //! \note This method is only guaranteed to function on `FILE*` objects
+  //!     referring to disk-based files.
+  FileOffset Seek(FileOffset offset, int whence) override;
+
+ private:
+  FILE* file_;  // weak
+
+  DISALLOW_COPY_AND_ASSIGN(WeakStdioFileReader);
+};
+
 }  // namespace crashpad
 
 #endif  // CRASHPAD_UTIL_FILE_FILE_READER_H_