[Lldb-commits] [PATCH] D50161: Add raw_ostream wrapper to the Stream class

[Raphael Isemann via Phabricator via lldb-commits]

teemperor updated this revision to Diff 158926.
teemperor added a reviewer: labath.
teemperor added a comment.

- Renamed m_forward_to to m_target.
- Added a getter to allow external code to use the raw_ostream API.
- Renamed m_forward to m_forwarder.

@labath Thanks, fixed the problems you pointed out. I already made the API public in this patch, it's probably good for encouraging people to use LLVM's raw_ostream classes.


https://reviews.llvm.org/D50161

Files:
  include/lldb/Utility/Stream.h
  source/Utility/Stream.cpp


Index: source/Utility/Stream.cpp
===================================================================
--- source/Utility/Stream.cpp
+++ source/Utility/Stream.cpp
@@ -23,11 +23,11 @@
 
 Stream::Stream(uint32_t flags, uint32_t addr_size, ByteOrder byte_order)
     : m_flags(flags), m_addr_size(addr_size), m_byte_order(byte_order),
-      m_indent_level(0) {}
+      m_indent_level(0), m_forwarder(*this) {}
 
 Stream::Stream()
     : m_flags(0), m_addr_size(4), m_byte_order(endian::InlHostByteOrder()),
-      m_indent_level(0) {}
+      m_indent_level(0), m_forwarder(*this) {}
 
 //------------------------------------------------------------------
 // Destructor
Index: include/lldb/Utility/Stream.h
===================================================================
--- include/lldb/Utility/Stream.h
+++ include/lldb/Utility/Stream.h
@@ -15,6 +15,7 @@
 #include "lldb/lldb-enumerations.h" // for ByteOrder::eByteOrderInvalid
 #include "llvm/ADT/StringRef.h"     // for StringRef
 #include "llvm/Support/FormatVariadic.h"
+#include "llvm/Support/raw_ostream.h"
 
 #include <stdarg.h>
 #include <stddef.h>    // for size_t
@@ -52,6 +53,17 @@
   //------------------------------------------------------------------
   Stream();
 
+  // FIXME: Streams should not be copyable.
+  Stream(const Stream &other) : m_forwarder(*this) { (*this) = other; }
+
+  Stream &operator=(const Stream &rhs) {
+    m_flags = rhs.m_flags;
+    m_addr_size = rhs.m_addr_size;
+    m_byte_order = rhs.m_byte_order;
+    m_indent_level = rhs.m_indent_level;
+    return *this;
+  }
+
   //------------------------------------------------------------------
   /// Destructor
   //------------------------------------------------------------------
@@ -520,6 +532,13 @@
   //------------------------------------------------------------------
   size_t PutULEB128(uint64_t uval);
 
+  //------------------------------------------------------------------
+  /// Returns a raw_ostream that forwards the data to this Stream object.
+  //------------------------------------------------------------------
+  llvm::raw_ostream &AsRawOstream() {
+    return m_forwarder;
+  }
+
 protected:
   //------------------------------------------------------------------
   // Member variables
@@ -548,6 +567,34 @@
   ///     The number of bytes that were appended to the stream.
   //------------------------------------------------------------------
   virtual size_t WriteImpl(const void *src, size_t src_len) = 0;
+
+  //----------------------------------------------------------------------
+  /// @class RawOstreamForward Stream.h "lldb/Utility/Stream.h"
+  /// This is a wrapper class that exposes a raw_ostream interface that just
+  /// forwards to an LLDB stream, allowing to reuse LLVM algorithms that take
+  /// a raw_ostream within the LLDB code base.
+  //----------------------------------------------------------------------
+  class RawOstreamForward : public llvm::raw_ostream {
+    // Note: This stream must *not* maintain its own buffer, but instead
+    // directly write everything to the internal Stream class. Without this,
+    // we would run into the problem that the Stream written byte count would
+    // differ from the actually written bytes by the size of the internal
+    // raw_ostream buffer.
+
+    Stream &m_target;
+    void write_impl(const char *Ptr, size_t Size) override {
+      m_target.Write(Ptr, Size);
+    }
+
+    uint64_t current_pos() const override {
+      return m_target.GetWrittenBytes();
+    }
+
+  public:
+    RawOstreamForward(Stream &target)
+        : llvm::raw_ostream(/*unbuffered*/ true), m_target(target) {}
+  };
+  RawOstreamForward m_forwarder;
 };
 
 } // namespace lldb_private


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