Introduce a new tool_output_file class, which extends raw_ostream with

functionality that most command-line tools need: ensuring that the
output file gets deleted if the tool is interrupted or encounters an
error.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111595 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/FormattedStream.h

@@ -19,10 +19,14 @@
 
 namespace llvm 
 {
+  class formatted_tool_output_file;
+
   /// formatted_raw_ostream - Formatted raw_fd_ostream to handle
   /// asm-specific constructs.
   ///
   class formatted_raw_ostream : public raw_ostream {
+    friend class formatted_tool_output_file;
+
   public:
     /// DELETE_STREAM - Tell the destructor to delete the held stream.
     ///
@@ -136,6 +140,25 @@ namespace llvm
     }
   };
 
+  /// formatted_tool_output_file - This is a subclass of formatted_raw_ostream
+  /// for use when the underlying stream is a tool_output_file. It exposes
+  /// the keep() member function.
+  class formatted_tool_output_file : public formatted_raw_ostream {
+  public:
+    formatted_tool_output_file(tool_output_file &Stream, bool Delete = false) 
+      : formatted_raw_ostream(Stream, Delete) {}
+
+    formatted_tool_output_file() {}
+
+    ~formatted_tool_output_file();
+
+    void setStream(tool_output_file &Stream, bool Delete = false) {
+      return formatted_raw_ostream::setStream(Stream, Delete);
+    }
+
+    void keep() { return static_cast<tool_output_file *>(TheStream)->keep(); }
+  };
+
 /// fouts() - This returns a reference to a formatted_raw_ostream for
 /// standard output.  Use it like: fouts() << "foo" << "bar";
 formatted_raw_ostream &fouts();

include/llvm/Support/raw_ostream.h

@@ -370,10 +370,11 @@ public:
   ~raw_fd_ostream();
 
   /// close - Manually flush the stream and close the file.
+  /// Note that this does not call fsync.
   void close();
 
   /// seek - Flushes the stream and repositions the underlying file descriptor
-  ///  positition to the offset specified from the beginning of the file.
+  /// positition to the offset specified from the beginning of the file.
   uint64_t seek(uint64_t off);
 
   virtual raw_ostream &changeColor(enum Colors colors, bool bold=false,
@@ -484,6 +485,25 @@ public:
   ~raw_null_ostream();
 };
 
+/// tool_output_file - This class behaves like a raw_fd_ostream but adds a
+/// few extra features commonly needed for compiler-like tool output files:
+///   - The file is automatically deleted if the process is killed.
+///   - The file is automatically deleted when the tool_output_file
+///     object is destroyed unless the client calls keep().
+class tool_output_file : public raw_fd_ostream {
+  std::string Filename;
+  bool Keep;
+public:
+  tool_output_file(const char *filename, std::string &ErrorInfo,
+                   unsigned Flags = 0);
+
+  ~tool_output_file();
+
+  /// keep - Indicate that the tool's job wrt this output file has been
+  /// successful and the file should not be deleted.
+  void keep() { Keep = true; }
+};
+
 } // end llvm namespace
 
 #endif