From c2ae897b02bfb67ed2ecc6048ecc494eb61be52a Mon Sep 17 00:00:00 2001
From: Peter Johnson <johnson.peter@gmail.com>
Date: Fri, 2 Sep 2016 20:53:45 -0700
Subject: [PATCH] Change API of raw_istream to be more similar to raw_ostream.

---
 src/WireDecoder.h                            |  4 ++--
 wpiutil/include/support/raw_istream.h        | 24 ++++++++++++++++----
 wpiutil/include/support/raw_socket_istream.h | 10 ++++----
 wpiutil/src/support/leb128.cpp               |  3 ++-
 wpiutil/src/support/raw_istream.cpp          | 10 +++++---
 wpiutil/src/support/raw_socket_istream.cpp   |  9 +++++---
 6 files changed, 43 insertions(+), 17 deletions(-)

diff --git a/src/WireDecoder.h b/src/WireDecoder.h
index 1063072c88..0136910843 100644
--- a/src/WireDecoder.h
+++ b/src/WireDecoder.h
@@ -52,7 +52,7 @@ class WireDecoder {
   bool Read(const char** buf, std::size_t len) {
     if (len > m_allocated) Realloc(len);
     *buf = m_buf;
-    bool rv = m_is.read(m_buf, len);
+    m_is.read(m_buf, len);
 #if 0
     nt::Logger& logger = nt::Logger::GetInstance();
     if (logger.min_level() <= NT_LOG_DEBUG4 && logger.HasLogger()) {
@@ -67,7 +67,7 @@ class WireDecoder {
       logger.Log(NT_LOG_DEBUG4, __FILE__, __LINE__, oss.str().c_str());
     }
 #endif
-    return rv;
+    return !m_is.has_error();
   }
 
   /* Reads a single byte. */
diff --git a/wpiutil/include/support/raw_istream.h b/wpiutil/include/support/raw_istream.h
index aeca34fe88..9407b94922 100644
--- a/wpiutil/include/support/raw_istream.h
+++ b/wpiutil/include/support/raw_istream.h
@@ -16,21 +16,37 @@ class raw_istream {
  public:
   raw_istream() = default;
   virtual ~raw_istream() = default;
-  virtual bool read(void* data, std::size_t len) = 0;
+
+  raw_istream& read(void* data, std::size_t len) {
+    read_impl(data, len);
+    return *this;
+  }
+
   virtual void close() = 0;
 
+  bool has_error() const { return m_error; }
+  void clear_error() { m_error = false; }
+
   raw_istream(const raw_istream&) = delete;
   raw_istream& operator=(const raw_istream&) = delete;
+
+ protected:
+  void error_detected() { m_error = true; }
+
+ private:
+  virtual void read_impl(void* data, std::size_t len) = 0;
+
+  bool m_error = false;
 };
 
 class raw_mem_istream : public raw_istream {
  public:
   raw_mem_istream(const char* mem, std::size_t len) : m_cur(mem), m_left(len) {}
-  virtual ~raw_mem_istream() = default;
-  virtual bool read(void* data, std::size_t len);
-  virtual void close() {}
+  void close() override;
 
  private:
+  void read_impl(void* data, std::size_t len) override;
+
   const char* m_cur;
   std::size_t m_left;
 };
diff --git a/wpiutil/include/support/raw_socket_istream.h b/wpiutil/include/support/raw_socket_istream.h
index 78b0517325..ab65f73b29 100644
--- a/wpiutil/include/support/raw_socket_istream.h
+++ b/wpiutil/include/support/raw_socket_istream.h
@@ -9,19 +9,21 @@
 #define WPIUTIL_SUPPORT_RAW_SOCKET_ISTREAM_H_
 
 #include "support/raw_istream.h"
-#include "tcpsockets/NetworkStream.h"
 
 namespace wpi {
 
+class NetworkStream;
+
 class raw_socket_istream : public raw_istream {
  public:
   raw_socket_istream(NetworkStream& stream, int timeout = 0)
       : m_stream(stream), m_timeout(timeout) {}
-  virtual ~raw_socket_istream() = default;
-  virtual bool read(void* data, std::size_t len);
-  virtual void close();
+
+  void close() override;
 
  private:
+  void read_impl(void* data, std::size_t len) override;
+
   NetworkStream& m_stream;
   int m_timeout;
 };
diff --git a/wpiutil/src/support/leb128.cpp b/wpiutil/src/support/leb128.cpp
index 002ee43673..11605bc3d6 100644
--- a/wpiutil/src/support/leb128.cpp
+++ b/wpiutil/src/support/leb128.cpp
@@ -103,7 +103,8 @@ bool ReadUleb128(raw_istream& is, unsigned long* ret) {
 
   while (1) {
     unsigned char byte;
-    if (!is.read((char*)&byte, 1)) return false;
+    is.read((char*)&byte, 1);
+    if (is.has_error()) return false;
 
     result |= (byte & 0x7f) << shift;
     shift += 7;
diff --git a/wpiutil/src/support/raw_istream.cpp b/wpiutil/src/support/raw_istream.cpp
index 13af6b97a8..24e8f08b83 100644
--- a/wpiutil/src/support/raw_istream.cpp
+++ b/wpiutil/src/support/raw_istream.cpp
@@ -11,10 +11,14 @@
 
 using namespace wpi;
 
-bool raw_mem_istream::read(void* data, std::size_t len) {
-  if (len > m_left) return false;
+void raw_mem_istream::close() {}
+
+void raw_mem_istream::read_impl(void* data, std::size_t len) {
+  if (len > m_left) {
+    error_detected();
+    return;
+  }
   std::memcpy(data, m_cur, len);
   m_cur += len;
   m_left -= len;
-  return true;
 }
diff --git a/wpiutil/src/support/raw_socket_istream.cpp b/wpiutil/src/support/raw_socket_istream.cpp
index a4dd1e4d5a..4d311b25b5 100644
--- a/wpiutil/src/support/raw_socket_istream.cpp
+++ b/wpiutil/src/support/raw_socket_istream.cpp
@@ -6,10 +6,11 @@
 /*----------------------------------------------------------------------------*/
 
 #include "support/raw_socket_istream.h"
+#include "tcpsockets/NetworkStream.h"
 
 using namespace wpi;
 
-bool raw_socket_istream::read(void* data, std::size_t len) {
+void raw_socket_istream::read_impl(void* data, std::size_t len) {
   char* cdata = static_cast<char*>(data);
   std::size_t pos = 0;
 
@@ -17,10 +18,12 @@ bool raw_socket_istream::read(void* data, std::size_t len) {
     NetworkStream::Error err;
     std::size_t count =
         m_stream.receive(&cdata[pos], len - pos, &err, m_timeout);
-    if (count == 0) return false;
+    if (count == 0) {
+      error_detected();
+      return;
+    }
     pos += count;
   }
-  return true;
 }
 
 void raw_socket_istream::close() { m_stream.close(); }