lang/c/msgpack: C++ binding: safer memory managent

git-svn-id: file:///Users/frsyuki/project/msgpack-git/svn/x@68 5a5092ae-2292-43ba-b2d5-dcab9c1a2731

cpp/Makefile.am

@@ -14,9 +14,11 @@ nobase_include_HEADERS = \
 		msgpack/type.hpp \
 		msgpack/type/array.hpp \
 		msgpack/type/boolean.hpp \
+		msgpack/type/float.hpp \
 		msgpack/type/integer.hpp \
 		msgpack/type/map.hpp \
 		msgpack/type/nil.hpp \
+		msgpack/type/raw.hpp \
 		msgpack/type/tuple.hpp
 
 noinst_HEADERS = \

cpp/test.cpp

@@ -152,9 +152,7 @@ int main(void)
 		unsigned num_msg = 0;
 		static const size_t RESERVE_SIZE = 32;//*1024;
 
-		std::auto_ptr<zone> pz(new zone());
-
-		unpacker pac(*pz);
+		unpacker pac;
 
 		while(stream.good() && total_bytes > 0) {
 
@@ -179,13 +177,15 @@ int main(void)
 				// 5.1. take out the parsed object
 				object o = pac.data();
 
-				// do something using pz and o
+				// 5.2 release the zone
+				std::auto_ptr<zone> olife( pac.release_zone() );
+
+				// 5.3 re-initialize the unpacker */
+				pac.reset();
+
+				// do some with the o and olife
 				std::cout << "message parsed: " << o << std::endl;
 				++num_msg;
-
-				// 5.3 re-initialize unpacker with next zone */
-				pz.reset(new zone());
-				pac.reset(*pz);
 			}
 
 		}

cpp/unpack.cpp

@@ -178,12 +178,13 @@ private:
 };
 
 
-unpacker::unpacker(zone& z) :
-	m_ctx(new context(&z)),
+unpacker::unpacker() :
 	m_buffer(NULL),
 	m_used(0),
 	m_free(0),
-	m_off(0)
+	m_off(0),
+	m_zone(new zone()),
+	m_ctx(new context(&*m_zone))
 { }
 
 
@@ -201,14 +202,14 @@ void unpacker::expand_buffer(size_t len)
 		else { next_size = UNPACKER_INITIAL_BUFFER_SIZE; }
 		while(next_size < len + m_used) { next_size *= 2; }
 
-		m_buffer = m_ctx->user()->realloc(m_buffer, next_size);
+		m_buffer = m_zone->realloc(m_buffer, next_size);
 		m_free = next_size - m_used;
 
 	} else {
 		size_t next_size = UNPACKER_INITIAL_BUFFER_SIZE;
 		while(next_size < len + m_used - m_off) { next_size *= 2; }
 
-		char* tmp = m_ctx->user()->malloc(next_size);
+		char* tmp = m_zone->malloc(next_size);
 		memcpy(tmp, m_buffer+m_off, m_used-m_off);
 
 		m_buffer = tmp;
@@ -226,20 +227,49 @@ bool unpacker::execute()
 	} else if(ret == 0) {
 		return false;
 	} else {
-		expand_buffer(0);
 		return true;
 	}
 }
 
+zone* unpacker::release_zone()
+{
+	zone* n = new zone();
+	std::auto_ptr<zone> old(m_zone.release());
+	m_zone.reset(n);
+
+	//std::auto_ptr<zone> old(new zone());
+	//m_zone.swap(old);
+
+	// move all bytes in m_buffer to new buffer from the new zone
+	if(m_used <= m_off) {
+		m_buffer = NULL;
+		m_used = 0;
+		m_free = 0;
+		m_off = 0;
+	} else {
+		try {
+			expand_buffer(0);
+		} catch (...) {
+			// m_zone.swap(old);
+			zone* tmp = old.release();
+			old.reset(m_zone.release());
+			m_zone.reset(tmp);
+			throw;
+		}
+	}
+	m_ctx->user(&*m_zone);
+	return old.release();
+}
+
 object unpacker::data()
 {
 	return m_ctx->data();
 }
 
-void unpacker::reset(zone& z)
+void unpacker::reset()
 {
-	if(m_off != 0) { expand_buffer(0); }
-	m_ctx->reset(&z);
+	if(m_off != 0) { std::auto_ptr<zone> old(release_zone()); }
+	m_ctx->reset();
 }
 
 

cpp/unpack.hpp

@@ -20,6 +20,7 @@
 
 #include "msgpack/object.hpp"
 #include "msgpack/zone.hpp"
+#include <memory>
 #include <stdexcept>
 
 #ifndef MSGPACK_UNPACKER_INITIAL_BUFFER_SIZE
@@ -40,7 +41,7 @@ struct unpack_error : public std::runtime_error {
 
 class unpacker {
 public:
-	unpacker(zone& z);
+	unpacker();
 	~unpacker();
 
 public:
@@ -60,8 +61,52 @@ public:
 	/*! 5.1. if execute() returns true, take out the parsed object */
 	object data();
 
-	/*! 5.2. re-initialize unpacker with next zone */
-	void reset(zone& z);
+	/*! 5.2. the object is valid until the zone is deleted */
+	// Note that once release_zone() from unpacker, you must delete it
+	// otherwise the memrory will leak.
+	zone* release_zone();
+
+	/*! 5.3. after release_zone(), re-initialize unpacker */
+	void reset();
+
+
+	// Basic usage of the unpacker is as following:
+	//
+	// msgpack::unpacker pac;
+	//
+	// while( /* readable */ ) {
+	//
+	//     // 1.
+	//     pac.reserve(1024);
+	//
+	//     // 2.
+	//     ssize_t bytes =
+	//         read(the_source, pac.buffer, pac.buffer_capacity());
+	//
+	//     // error handling ...
+	//
+	//     // 3.
+	//     pac.buffer_consumed(bytes);
+	//
+	//     // 4.
+	//     while(pac.execute()) {
+	//         // 5.1
+	//         object o = pac.data();
+	//
+	//         // 5.2
+	//         std::auto_ptr<msgpack::zone> olife( pac.release_zone() );
+	//
+	//         // boost::shared_ptr is also usable:
+	//         // boost::shared_ptr<msgpack::zone> olife( pac.release_zone() );
+	//
+	//         // 5.3
+	//         pac.reset();
+	//
+	//         // do some with the object with the old zone.
+	//         do_something(o, olife);
+	//     }
+	// }
+	//
 
 public:
 	// These functions are usable when non-MessagePack message follows after
@@ -80,19 +125,20 @@ public:
 	void remove_nonparsed_buffer();
 
 private:
-	struct context;
-	context* m_ctx;
-
 	char* m_buffer;
 	size_t m_used;
 	size_t m_free;
 	size_t m_off;
 
+	std::auto_ptr<zone> m_zone;
+
+	struct context;
+	context* m_ctx;
+
 private:
 	void expand_buffer(size_t len);
 
 private:
-	unpacker();
 	unpacker(const unpacker&);
 
 public: