Merge pull request #144 from scottpurdy/std-compat

Adds kj::std as header-only compat layer

CONTRIBUTORS

@@ -6,6 +6,7 @@ Kenton Varda <temporal@gmail.com>: Primary Author
 Jason Choy <jjwchoy@gmail.com>: kj/threadlocal.h and other iOS tweaks, `name` annotation in C++ code generator
 Remy Blank <rblank@google.com> (contributions copyright Google Inc.): KJ Timers
 Joshua Warner <joshuawarner32@gmail.com>: cmake build
+Scott Purdy <scott@fer.io>: kj/std iostream interface
 
 This file does not list people who maintain their own Cap'n Proto
 implementations as separate projects.  Those people are awesome too!  :)

c++/Makefile.am

@@ -117,6 +117,7 @@ capnpc_outputs =                                               \
 includecapnpdir = $(includedir)/capnp
 includekjdir = $(includedir)/kj
 includekjparsedir = $(includekjdir)/parse
+includekjstddir = $(includekjdir)/std
 
 dist_includecapnp_DATA = $(public_capnpc_inputs)
 
@@ -154,6 +155,9 @@ includekjparse_HEADERS =                                       \
   src/kj/parse/common.h                                        \
   src/kj/parse/char.h
 
+includekjstd_HEADERS =                                         \
+  src/kj/std/iostream.h
+
 includecapnp_HEADERS =                                         \
   src/capnp/c++.capnp.h                                        \
   src/capnp/common.h                                           \
@@ -372,6 +376,7 @@ heavy_tests =                                                  \
   src/kj/async-io-test.c++                                     \
   src/kj/parse/common-test.c++                                 \
   src/kj/parse/char-test.c++                                   \
+  src/kj/std/iostream-test.c++                                 \
   src/capnp/capability-test.c++                                \
   src/capnp/schema-test.c++                                    \
   src/capnp/schema-loader-test.c++                             \

c++/src/kj/CMakeLists.txt

@@ -45,10 +45,14 @@ set(kj-parse_headers
   parse/common.h
   parse/char.h
 )
+set(kj-std_headers
+  std/iostream.h
+)
 add_library(kj ${kj_sources})
 install(TARGETS kj ARCHIVE DESTINATION "${LIB_INSTALL_DIR}")
 install(FILES ${kj_headers} DESTINATION "${INCLUDE_INSTALL_DIR}/kj")
 install(FILES ${kj-parse_headers} DESTINATION "${INCLUDE_INSTALL_DIR}/kj/parse")
+install(FILES ${kj-std_headers} DESTINATION "${INCLUDE_INSTALL_DIR}/kj/std")
 
 set(kj-async_sources
   async.c++
@@ -103,6 +107,7 @@ if(BUILD_TESTING)
       async-io-test.c++
       parse/common-test.c++
       parse/char-test.c++
+      std/iostream-test.c++
     )
     target_link_libraries(kj-heavy-tests kj kj-async gtest gtest_main)
     add_dependencies(check kj-heavy-tests)

c++/src/kj/std/iostream-test.c++

+// Copyright (c) 2014 Sandstorm Development Group, Inc. and contributors
+// Licensed under the MIT License:
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#include "iostream.h"
+#include <sstream>
+#include <gtest/gtest.h>
+
+namespace kj {
+namespace std {
+namespace {
+
+TEST(StdIoStream, WriteVec) {
+  // Check that writing an array of arrays works even when some of the arrays
+  // are empty.  (This used to not work in some cases.)
+
+  ::std::stringstream ss;
+
+  StdInputStream in(ss);
+  StdOutputStream out(ss);
+
+  ArrayPtr<const byte> pieces[5] = {
+    arrayPtr(implicitCast<const byte*>(nullptr), 0),
+    arrayPtr(reinterpret_cast<const byte*>("foo"), 3),
+    arrayPtr(implicitCast<const byte*>(nullptr), 0),
+    arrayPtr(reinterpret_cast<const byte*>("bar"), 3),
+    arrayPtr(implicitCast<const byte*>(nullptr), 0)
+  };
+
+  out.write(pieces);
+
+  char buf[7];
+  in.read(buf, 6);
+  buf[6] = '\0';
+
+  EXPECT_STREQ("foobar", buf);
+}
+
+TEST(StdIoStream, TryReadToEndOfFile) {
+  // Check that tryRead works when eof is reached before minBytes.
+
+  ::std::stringstream ss;
+
+  StdInputStream in(ss);
+  StdOutputStream out(ss);
+
+  const void* bytes = "foobar";
+
+  out.write(bytes, 6);
+
+  char buf[9];
+  in.tryRead(buf, 8, 8);
+  buf[6] = '\0';
+
+  EXPECT_STREQ("foobar", buf);
+}
+
+TEST(StdIoStream, ReadToEndOfFile) {
+  // Check that read throws an exception when eof is reached before specified
+  // bytes.
+
+  ::std::stringstream ss;
+
+  StdInputStream in(ss);
+  StdOutputStream out(ss);
+
+  const void* bytes = "foobar";
+
+  out.write(bytes, 6);
+
+  char buf[9];
+
+  Maybe<Exception> e = kj::runCatchingExceptions([&]() {
+    in.read(buf, 8, 8);
+  });
+  buf[6] = '\0';
+
+  KJ_IF_MAYBE(ex, e) {
+    // Ensure that the value is still read up to the EOF.
+    EXPECT_STREQ("foobar", buf);
+  } else {
+    ADD_FAILURE() << "Expected exception";
+  }
+}
+
+}  // namespace
+}  // namespace std
+}  // namespace kj

c++/src/kj/std/iostream.h

+// Copyright (c) 2014 Sandstorm Development Group, Inc. and contributors
+// Licensed under the MIT License:
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+/*
+ * Compatibility layer for stdlib iostream
+ */
+
+#ifndef KJ_STD_IOSTREAM_H_
+#define KJ_STD_IOSTREAM_H_
+
+#include <iostream>
+#include "../io.h"
+
+namespace kj {
+namespace std {
+
+class StdOutputStream: public kj::OutputStream {
+
+public:
+  explicit StdOutputStream(::std::ostream& stream) : stream_(stream) {}
+  ~StdOutputStream() noexcept(false) {}
+
+  virtual void write(const void* src, size_t size) override {
+    // Always writes the full size.
+
+    stream_.write((char*)src, size);
+  }
+
+  virtual void write(ArrayPtr<const ArrayPtr<const byte>> pieces) override {
+    // Equivalent to write()ing each byte array in sequence, which is what the
+    // default implementation does. Override if you can do something better,
+    // e.g. use writev() to do the write in a single syscall.
+
+    for (auto piece : pieces) {
+      write(piece.begin(), piece.size());
+    }
+  }
+
+private:
+  ::std::ostream& stream_;
+
+};
+
+class StdInputStream: public kj::InputStream {
+
+public:
+  explicit StdInputStream(::std::istream& stream) : stream_(stream) {}
+  ~StdInputStream() noexcept(false) {}
+
+  virtual size_t tryRead(
+      void* buffer, size_t minBytes, size_t maxBytes) override {
+    // Like read(), but may return fewer than minBytes on EOF.
+
+    stream_.read((char*)buffer, maxBytes);
+    return stream_.gcount();
+  }
+
+private:
+  ::std::istream& stream_;
+
+};
+
+}  // namespace std
+}  // namespace kj
+
+#endif  // KJ_STD_IOSTREAM_H_