From b25a8db2a601bb5b4c4d7b463fd4d1687b913535 Mon Sep 17 00:00:00 2001
From: Arvid Norberg <arvid@libtorrent.org>
Date: Mon, 23 Feb 2009 01:21:19 +0000
Subject: [PATCH] added more error codes. consolidated exception classes into
 one. moved over more places to use error_code instead of strings. fixed
 proper error handling for torrent_info

---
 docs/manual.html                         | 180 +++++++++++++++++----
 docs/manual.rst                          | 152 ++++++++++--------
 include/libtorrent/aux_/session_impl.hpp |   2 +-
 include/libtorrent/entry.hpp             |  25 ++-
 include/libtorrent/error_code.hpp        |  31 +++-
 include/libtorrent/escape_string.hpp     |   3 +-
 include/libtorrent/session.hpp           |   1 +
 include/libtorrent/torrent.hpp           |  11 +-
 include/libtorrent/torrent_handle.hpp    |  17 +-
 include/libtorrent/torrent_info.hpp      |  19 ++-
 src/create_torrent.cpp                   |  10 +-
 src/error_code.cpp                       |   9 ++
 src/escape_string.cpp                    |  30 ++--
 src/magnet_uri.cpp                       |  10 +-
 src/peer_connection.cpp                  |   6 +-
 src/session.cpp                          |  18 ++-
 src/session_impl.cpp                     |  20 +--
 src/torrent.cpp                          |  37 ++---
 src/torrent_handle.cpp                   |  12 +-
 src/torrent_info.cpp                     | 195 +++++++++++++++--------
 20 files changed, 518 insertions(+), 270 deletions(-)

diff --git a/docs/manual.html b/docs/manual.html
index febcde363..32fd071c8 100644
--- a/docs/manual.html
+++ b/docs/manual.html
@@ -220,44 +220,46 @@
 <li><a class="reference internal" href="#invalid-torrent-file" id="id173">invalid_torrent_file</a></li>
 </ul>
 </li>
-<li><a class="reference internal" href="#storage-interface" id="id174">storage_interface</a><ul>
-<li><a class="reference internal" href="#initialize" id="id175">initialize()</a></li>
-<li><a class="reference internal" href="#readv-writev" id="id176">readv() writev()</a></li>
-<li><a class="reference internal" href="#id12" id="id177">move_storage()</a></li>
-<li><a class="reference internal" href="#verify-resume-data" id="id178">verify_resume_data()</a></li>
-<li><a class="reference internal" href="#write-resume-data" id="id179">write_resume_data()</a></li>
-<li><a class="reference internal" href="#move-slot" id="id180">move_slot()</a></li>
-<li><a class="reference internal" href="#swap-slots" id="id181">swap_slots()</a></li>
-<li><a class="reference internal" href="#swap-slots3" id="id182">swap_slots3()</a></li>
-<li><a class="reference internal" href="#hash-for-slot" id="id183">hash_for_slot()</a></li>
-<li><a class="reference internal" href="#id13" id="id184">rename_file()</a></li>
-<li><a class="reference internal" href="#release-files" id="id185">release_files()</a></li>
-<li><a class="reference internal" href="#delete-files" id="id186">delete_files()</a></li>
+<li><a class="reference internal" href="#error-code" id="id174">error_code</a></li>
+<li><a class="reference internal" href="#storage-interface" id="id175">storage_interface</a><ul>
+<li><a class="reference internal" href="#initialize" id="id176">initialize()</a></li>
+<li><a class="reference internal" href="#readv-writev" id="id177">readv() writev()</a></li>
+<li><a class="reference internal" href="#sparse-end" id="id178">sparse_end()</a></li>
+<li><a class="reference internal" href="#id12" id="id179">move_storage()</a></li>
+<li><a class="reference internal" href="#verify-resume-data" id="id180">verify_resume_data()</a></li>
+<li><a class="reference internal" href="#write-resume-data" id="id181">write_resume_data()</a></li>
+<li><a class="reference internal" href="#move-slot" id="id182">move_slot()</a></li>
+<li><a class="reference internal" href="#swap-slots" id="id183">swap_slots()</a></li>
+<li><a class="reference internal" href="#swap-slots3" id="id184">swap_slots3()</a></li>
+<li><a class="reference internal" href="#hash-for-slot" id="id185">hash_for_slot()</a></li>
+<li><a class="reference internal" href="#id13" id="id186">rename_file()</a></li>
+<li><a class="reference internal" href="#release-files" id="id187">release_files()</a></li>
+<li><a class="reference internal" href="#delete-files" id="id188">delete_files()</a></li>
 </ul>
 </li>
-<li><a class="reference internal" href="#magnet-links" id="id187">magnet links</a></li>
-<li><a class="reference internal" href="#queuing" id="id188">queuing</a><ul>
-<li><a class="reference internal" href="#downloading" id="id189">downloading</a></li>
-<li><a class="reference internal" href="#seeding" id="id190">seeding</a></li>
+<li><a class="reference internal" href="#magnet-links" id="id189">magnet links</a></li>
+<li><a class="reference internal" href="#queuing" id="id190">queuing</a><ul>
+<li><a class="reference internal" href="#downloading" id="id191">downloading</a></li>
+<li><a class="reference internal" href="#seeding" id="id192">seeding</a></li>
 </ul>
 </li>
-<li><a class="reference internal" href="#fast-resume" id="id191">fast resume</a><ul>
-<li><a class="reference internal" href="#file-format" id="id192">file format</a></li>
+<li><a class="reference internal" href="#fast-resume" id="id193">fast resume</a><ul>
+<li><a class="reference internal" href="#file-format" id="id194">file format</a></li>
 </ul>
 </li>
-<li><a class="reference internal" href="#threads" id="id193">threads</a></li>
-<li><a class="reference internal" href="#storage-allocation" id="id194">storage allocation</a><ul>
-<li><a class="reference internal" href="#sparse-allocation" id="id195">sparse allocation</a></li>
-<li><a class="reference internal" href="#full-allocation" id="id196">full allocation</a></li>
-<li><a class="reference internal" href="#compact-allocation" id="id197">compact allocation</a></li>
+<li><a class="reference internal" href="#threads" id="id195">threads</a></li>
+<li><a class="reference internal" href="#storage-allocation" id="id196">storage allocation</a><ul>
+<li><a class="reference internal" href="#sparse-allocation" id="id197">sparse allocation</a></li>
+<li><a class="reference internal" href="#full-allocation" id="id198">full allocation</a></li>
+<li><a class="reference internal" href="#compact-allocation" id="id199">compact allocation</a></li>
 </ul>
 </li>
-<li><a class="reference internal" href="#extensions" id="id198">extensions</a><ul>
-<li><a class="reference internal" href="#metadata-from-peers" id="id199">metadata from peers</a></li>
-<li><a class="reference internal" href="#http-seeding" id="id200">HTTP seeding</a></li>
+<li><a class="reference internal" href="#extensions" id="id200">extensions</a><ul>
+<li><a class="reference internal" href="#metadata-from-peers" id="id201">metadata from peers</a></li>
+<li><a class="reference internal" href="#http-seeding" id="id202">HTTP seeding</a></li>
 </ul>
 </li>
-<li><a class="reference internal" href="#filename-checks" id="id201">filename checks</a></li>
+<li><a class="reference internal" href="#filename-checks" id="id203">filename checks</a></li>
 </ul>
 </div>
 <div class="section" id="overview">
@@ -1394,12 +1396,20 @@ class torrent_info
 {
 public:
 
+        // these constructors throws exceptions on error
         torrent_info(sha1_hash const&amp; info_hash);
         torrent_info(lazy_entry const&amp; torrent_file);
         torrent_info(char const* buffer, int size);
         torrent_info(boost::filesystem::path const&amp; filename);
         torrent_info(boost::filesystem::wpath const&amp; filename);
 
+        // these constructors sets the error code on error
+        torrent_info(sha1_hash const&amp; info_hash, error_code&amp; ec);
+        torrent_info(lazy_entry const&amp; torrent_file, error_code&amp; ec);
+        torrent_info(char const* buffer, int size, error_code&amp; ec);
+        torrent_info(fs::path const&amp; filename, error_code&amp; ec);
+        torrent_info(fs::wpath const&amp; filename, error_code&amp; ec);
+
         void add_tracker(std::string const&amp; url, int tier = 0);
         std::vector&lt;announce_entry&gt; const&amp; trackers() const;
 
@@ -1463,6 +1473,12 @@ torrent_info(lazy_entry const&amp; torrent_file);
 torrent_info(char const* buffer, int size);
 torrent_info(boost::filesystem::path const&amp; filename);
 torrent_info(boost::filesystem::wpath const&amp; filename);
+
+torrent_info(sha1_hash const&amp; info_hash, error_code&amp; ec);
+torrent_info(lazy_entry const&amp; torrent_file, error_code&amp; ec);
+torrent_info(char const* buffer, int size, error_code&amp; ec);
+torrent_info(fs::path const&amp; filename, error_code&amp; ec);
+torrent_info(fs::wpath const&amp; filename, error_code&amp; ec);
 </pre>
 </blockquote>
 <p>The constructor that takes an info-hash  will initialize the info-hash to the given value,
@@ -1478,6 +1494,11 @@ initialize the torrent_info object for you.</p>
 <p>The version that takes a filename will simply load the torrent file and decode it inside
 the constructor, for convenience. This might not be the most suitable for applications that
 want to be able to report detailed errors on what might go wrong.</p>
+<p>The overloads that takes an <tt class="docutils literal"><span class="pre">error_code</span> <span class="pre">const&amp;</span></tt> never throws if an error occur, they
+will simply set the error code to describe what went wrong and not fully initialize the
+torrent_info object. The overloads that do not take the extra <a class="reference internal" href="#error-code">error_code</a> parameter will
+always throw if an error occurs. These overloads are not available when building without
+exception support.</p>
 </div>
 <div class="section" id="add-tracker">
 <h2>add_tracker()</h2>
@@ -4774,10 +4795,100 @@ doesn't meet the requirements on what information has to be present in a torrent
 struct invalid_torrent_file: std::exception
 {
         const char* what() const throw();
+        boost::system::error_code error() const;
 };
 </pre>
 </div>
 </div>
+<div class="section" id="error-code">
+<h1>error_code</h1>
+<p>libtorrent uses boost.system's <tt class="docutils literal"><span class="pre">error_code</span></tt> class to represent errors. libtorrent has
+its own error category (<tt class="docutils literal"><span class="pre">libtorrent::libtorrent_category</span></tt>) whith the following error
+codes:</p>
+<table border="1" class="docutils">
+<colgroup>
+<col width="6%" />
+<col width="28%" />
+<col width="66%" />
+</colgroup>
+<thead valign="bottom">
+<tr><th class="head">code</th>
+<th class="head">symbol</th>
+<th class="head">description</th>
+</tr>
+</thead>
+<tbody valign="top">
+<tr><td>0</td>
+<td>no_error</td>
+<td>Not an error</td>
+</tr>
+<tr><td>1</td>
+<td>file_collision</td>
+<td>Two torrents has files which end up overwriting each other</td>
+</tr>
+<tr><td>2</td>
+<td>failed_hash_check</td>
+<td>A piece did not match its piece hash</td>
+</tr>
+<tr><td>3</td>
+<td>torrent_is_no_dict</td>
+<td>The .torrent file does not contain a bencoded dictionary at
+its top level</td>
+</tr>
+<tr><td>4</td>
+<td>torrent_missing_info</td>
+<td>The .torrent file does not have an <tt class="docutils literal"><span class="pre">info</span></tt> dictionary</td>
+</tr>
+<tr><td>5</td>
+<td>torrent_info_no_dict</td>
+<td>The .torrent file's <tt class="docutils literal"><span class="pre">info</span></tt> entry is not a dictionary</td>
+</tr>
+<tr><td>6</td>
+<td>torrent_missing_piece_length</td>
+<td>The .torrent file does not have a <tt class="docutils literal"><span class="pre">piece</span> <span class="pre">length</span></tt> entry</td>
+</tr>
+<tr><td>7</td>
+<td>torrent_missing_name</td>
+<td>The .torrent file does not have a <tt class="docutils literal"><span class="pre">name</span></tt> entry</td>
+</tr>
+<tr><td>8</td>
+<td>torrent_invalid_name</td>
+<td>The .torrent file's name entry is invalid</td>
+</tr>
+<tr><td>9</td>
+<td>torrent_invalid_length</td>
+<td>The length of a file, or of the whole .torrent file is invalid.
+Either negative or not an integer</td>
+</tr>
+<tr><td>10</td>
+<td>torrent_file_parse_failed</td>
+<td>Failed to parse a file entry in the .torrent</td>
+</tr>
+<tr><td>11</td>
+<td>torrent_missing_pieces</td>
+<td>The <tt class="docutils literal"><span class="pre">pieces</span></tt> field is missing or invalid in the .torrent file</td>
+</tr>
+<tr><td>12</td>
+<td>torrent_invalid_hashes</td>
+<td>The <tt class="docutils literal"><span class="pre">pieces</span></tt> string has incorrect length</td>
+</tr>
+<tr><td>13</td>
+<td>too_many_pieces_in_torrent</td>
+<td>The .torrent file has more pieces than is supported by libtorrent</td>
+</tr>
+<tr><td>14</td>
+<td>invalid_swarm_metadata</td>
+<td>The metadata (.torrent file) that was received from the swarm
+matched the info-hash, but failed to be parsed</td>
+</tr>
+<tr><td>15</td>
+<td>invalid_bencoding</td>
+<td>The file or buffer is not correctly bencoded</td>
+</tr>
+</tbody>
+</table>
+<p>The names of these error codes are declared in then <tt class="docutils literal"><span class="pre">libtorrent::errors</span></tt> namespace.</p>
+</div>
 <div class="section" id="storage-interface">
 <h1>storage_interface</h1>
 <p>The storage interface is a pure virtual class that can be implemented to
@@ -4789,6 +4900,7 @@ struct storage_interface
         virtual bool initialize(bool allocate_files) = 0;
         virtual int readv(file::iovec_t const* bufs, int slot, int offset, int num_bufs) = 0;
         virtual int writev(file::iovec_t const* bufs, int slot, int offset, int num_bufs) = 0;
+        virtual int sparse_end(int start) const;
         virtual bool move_storage(fs::path save_path) = 0;
         virtual bool verify_resume_data(lazy_entry const&amp; rd, std::string&amp; error) = 0;
         virtual bool write_resume_data(entry&amp; rd) const = 0;
@@ -4851,6 +4963,18 @@ exceptions when it's not. Specifically if the read cache is disabled/or full and
 client requests unaligned data, or the file itself is not aligned in the torrent.
 Most clients request aligned data.</p>
 </div>
+<div class="section" id="sparse-end">
+<h2>sparse_end()</h2>
+<blockquote>
+<pre class="literal-block">
+int sparse_end(int start) const;
+</pre>
+</blockquote>
+<p>This function is optional. It is supposed to return the first piece, starting at
+<tt class="docutils literal"><span class="pre">start</span></tt> that is fully contained within a data-region on disk (i.e. non-sparse
+region). The purpose of this is to skip parts of files that can be known to contain
+zeros when checking files.</p>
+</div>
 <div class="section" id="id12">
 <h2>move_storage()</h2>
 <blockquote>
diff --git a/docs/manual.rst b/docs/manual.rst
index 16a5487ea..0c887b3fb 100644
--- a/docs/manual.rst
+++ b/docs/manual.rst
@@ -1255,12 +1255,20 @@ The ``torrent_info`` has the following synopsis::
 	{
 	public:
 
+		// these constructors throws exceptions on error
 		torrent_info(sha1_hash const& info_hash);
 		torrent_info(lazy_entry const& torrent_file);
 		torrent_info(char const* buffer, int size);
 		torrent_info(boost::filesystem::path const& filename);
 		torrent_info(boost::filesystem::wpath const& filename);
 
+		// these constructors sets the error code on error
+		torrent_info(sha1_hash const& info_hash, error_code& ec);
+		torrent_info(lazy_entry const& torrent_file, error_code& ec);
+		torrent_info(char const* buffer, int size, error_code& ec);
+		torrent_info(fs::path const& filename, error_code& ec);
+		torrent_info(fs::wpath const& filename, error_code& ec);
+
 		void add_tracker(std::string const& url, int tier = 0);
 		std::vector<announce_entry> const& trackers() const;
 
@@ -1326,6 +1334,12 @@ torrent_info()
 		torrent_info(boost::filesystem::path const& filename);
 		torrent_info(boost::filesystem::wpath const& filename);
 
+		torrent_info(sha1_hash const& info_hash, error_code& ec);
+		torrent_info(lazy_entry const& torrent_file, error_code& ec);
+		torrent_info(char const* buffer, int size, error_code& ec);
+		torrent_info(fs::path const& filename, error_code& ec);
+		torrent_info(fs::wpath const& filename, error_code& ec);
+
 The constructor that takes an info-hash  will initialize the info-hash to the given value,
 but leave all other fields empty. This is used internally when downloading torrents without
 the metadata. The metadata will be created by libtorrent as soon as it has been downloaded
@@ -1343,6 +1357,12 @@ The version that takes a filename will simply load the torrent file and decode i
 the constructor, for convenience. This might not be the most suitable for applications that
 want to be able to report detailed errors on what might go wrong.
 
+The overloads that takes an ``error_code const&`` never throws if an error occur, they
+will simply set the error code to describe what went wrong and not fully initialize the
+torrent_info object. The overloads that do not take the extra error_code_ parameter will
+always throw if an error occurs. These overloads are not available when building without
+exception support.
+
 
 add_tracker()
 -------------
@@ -4914,80 +4934,84 @@ including ``<libtorrent/alert.hpp>``.
 exceptions
 ==========
 
-There are a number of exceptions that can be thrown from different places in libtorrent,
-here's a complete list with description.
+Many functions in libtorrent have two versions, one that throws exceptions on
+errors and one that takes an ``error_code`` reference which is filled with the
+error code on errors.
 
+There is one exception class that is used for errors in libtorrent, it is based
+on boost.system's ``error_code`` class to carry the error code.
 
-invalid_handle
---------------
-
-This exception is thrown when querying information from a torrent_handle_ that hasn't
-been initialized or that has become invalid.
-
-::
-
-	struct invalid_handle: std::exception
-	{
-		const char* what() const throw();
-	};
-
-
-duplicate_torrent
------------------
-
-This is thrown by `add_torrent()`_ if the torrent already has been added to
-the session. Since `remove_torrent()`_ is asynchronous, this exception may
-be thrown if the torrent is removed and then immediately added again.
-
-::
-
-	struct duplicate_torrent: std::exception
-	{
-		const char* what() const throw();
-	};
-
-
-invalid_encoding
-----------------
-
-This is thrown by ``bdecode()`` if the input data is not a valid bencoding.
-
-::
-
-	struct invalid_encoding: std::exception
-	{
-		const char* what() const throw();
-	};
-
-
-type_error
-----------
-
-This is thrown from the accessors of ``entry`` if the data type of the ``entry`` doesn't
-match the type you want to extract from it.
-
-::
-
-	struct type_error: std::runtime_error
-	{
-		type_error(const char* error);
-	};
-
-
-invalid_torrent_file
+libtorrent_exception
 --------------------
 
-This exception is thrown from the constructor of ``torrent_info`` if the given bencoded information
-doesn't meet the requirements on what information has to be present in a torrent file.
-
 ::
 
-	struct invalid_torrent_file: std::exception
+	struct libtorrent_exception: std::exception
 	{
-		const char* what() const throw();
+		libtorrent_exception(error_code const& s);
+		virtual const char* what() const throw();
+		virtual ~libtorrent_exception() throw() {}
+		boost::system::error_code error() const;
 	};
 
 
+error_code
+==========
+
+libtorrent uses boost.system's ``error_code`` class to represent errors. libtorrent has
+its own error category (``libtorrent::libtorrent_category``) whith the following error
+codes:
+
+====== ============================ =================================================================
+code   symbol                       description
+====== ============================ =================================================================
+0      no_error                     Not an error
+------ ---------------------------- -----------------------------------------------------------------
+1      file_collision               Two torrents has files which end up overwriting each other
+------ ---------------------------- -----------------------------------------------------------------
+2      failed_hash_check            A piece did not match its piece hash
+------ ---------------------------- -----------------------------------------------------------------
+3      torrent_is_no_dict           The .torrent file does not contain a bencoded dictionary at
+                                    its top level
+------ ---------------------------- -----------------------------------------------------------------
+4      torrent_missing_info         The .torrent file does not have an ``info`` dictionary
+------ ---------------------------- -----------------------------------------------------------------
+5      torrent_info_no_dict         The .torrent file's ``info`` entry is not a dictionary
+------ ---------------------------- -----------------------------------------------------------------
+6      torrent_missing_piece_length The .torrent file does not have a ``piece length`` entry
+------ ---------------------------- -----------------------------------------------------------------
+7      torrent_missing_name         The .torrent file does not have a ``name`` entry
+------ ---------------------------- -----------------------------------------------------------------
+8      torrent_invalid_name         The .torrent file's name entry is invalid
+------ ---------------------------- -----------------------------------------------------------------
+9      torrent_invalid_length       The length of a file, or of the whole .torrent file is invalid.
+                                    Either negative or not an integer
+------ ---------------------------- -----------------------------------------------------------------
+10     torrent_file_parse_failed    Failed to parse a file entry in the .torrent
+------ ---------------------------- -----------------------------------------------------------------
+11     torrent_missing_pieces       The ``pieces`` field is missing or invalid in the .torrent file
+------ ---------------------------- -----------------------------------------------------------------
+12     torrent_invalid_hashes       The ``pieces`` string has incorrect length
+------ ---------------------------- -----------------------------------------------------------------
+13     too_many_pieces_in_torrent   The .torrent file has more pieces than is supported by libtorrent
+------ ---------------------------- -----------------------------------------------------------------
+14     invalid_swarm_metadata       The metadata (.torrent file) that was received from the swarm
+                                    matched the info-hash, but failed to be parsed
+------ ---------------------------- -----------------------------------------------------------------
+15     invalid_bencoding            The file or buffer is not correctly bencoded
+------ ---------------------------- -----------------------------------------------------------------
+16     no_files_in_torrent          The .torrent file does not contain any files
+------ ---------------------------- -----------------------------------------------------------------
+17     invalid_escaped_string       The string was not properly url-encoded as expected
+------ ---------------------------- -----------------------------------------------------------------
+18     session_is_closing           Operation is not permitted since the session is shutting down
+------ ---------------------------- -----------------------------------------------------------------
+19     duplicate_torrent            There's already a torrent with that info-hash added to the
+                                    session
+====== ============================ =================================================================
+
+The names of these error codes are declared in then ``libtorrent::errors`` namespace.
+
 storage_interface
 =================
 
diff --git a/include/libtorrent/aux_/session_impl.hpp b/include/libtorrent/aux_/session_impl.hpp
index fe6626a8b..dbd8273ad 100644
--- a/include/libtorrent/aux_/session_impl.hpp
+++ b/include/libtorrent/aux_/session_impl.hpp
@@ -206,7 +206,7 @@ namespace libtorrent
 				, const char* net_interface = 0);
 			bool is_listening() const;
 
-			torrent_handle add_torrent(add_torrent_params const&);
+			torrent_handle add_torrent(add_torrent_params const&, error_code& ec);
 
 			void remove_torrent(torrent_handle const& h, int options);
 
diff --git a/include/libtorrent/entry.hpp b/include/libtorrent/entry.hpp
index a970bf81b..3f3b6e0a6 100644
--- a/include/libtorrent/entry.hpp
+++ b/include/libtorrent/entry.hpp
@@ -68,6 +68,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/size_type.hpp"
 #include "libtorrent/config.hpp"
 #include "libtorrent/assert.hpp"
+#include "libtorrent/error_code.hpp"
 
 namespace libtorrent
 {
@@ -224,6 +225,14 @@ namespace libtorrent
 		return os;
 	}
 
+#ifndef BOOST_NO_EXCEPTIONS
+	inline void throw_type_error()
+	{
+		throw libtorrent_exception(error_code(errors::invalid_entry_type
+			, libtorrent_category));
+	}
+#endif
+
 	inline entry::data_type entry::type() const
 	{
 #ifdef TORRENT_DEBUG
@@ -244,7 +253,7 @@ namespace libtorrent
 	{
 		if (m_type == undefined_t) construct(int_t);
 #ifndef BOOST_NO_EXCEPTIONS
-		if (m_type != int_t) throw type_error("invalid type requested from entry");
+		if (m_type != int_t) throw_type_error();
 #elif defined TORRENT_DEBUG
 		TORRENT_ASSERT(m_type_queried);
 #endif
@@ -255,7 +264,7 @@ namespace libtorrent
 	inline entry::integer_type const& entry::integer() const
 	{
 #ifndef BOOST_NO_EXCEPTIONS
-		if (m_type != int_t) throw type_error("invalid type requested from entry");
+		if (m_type != int_t) throw_type_error();
 #elif defined TORRENT_DEBUG
 		TORRENT_ASSERT(m_type_queried);
 #endif
@@ -267,7 +276,7 @@ namespace libtorrent
 	{
 		if (m_type == undefined_t) construct(string_t);
 #ifndef BOOST_NO_EXCEPTIONS
-		if (m_type != string_t) throw type_error("invalid type requested from entry");
+		if (m_type != string_t) throw_type_error();
 #elif defined TORRENT_DEBUG
 		TORRENT_ASSERT(m_type_queried);
 #endif
@@ -278,7 +287,7 @@ namespace libtorrent
 	inline entry::string_type const& entry::string() const
 	{
 #ifndef BOOST_NO_EXCEPTIONS
-		if (m_type != string_t) throw type_error("invalid type requested from entry");
+		if (m_type != string_t) throw_type_error();
 #elif defined TORRENT_DEBUG
 		TORRENT_ASSERT(m_type_queried);
 #endif
@@ -290,7 +299,7 @@ namespace libtorrent
 	{
 		if (m_type == undefined_t) construct(list_t);
 #ifndef BOOST_NO_EXCEPTIONS
-		if (m_type != list_t) throw type_error("invalid type requested from entry");
+		if (m_type != list_t) throw_type_error();
 #elif defined TORRENT_DEBUG
 		TORRENT_ASSERT(m_type_queried);
 #endif
@@ -301,7 +310,7 @@ namespace libtorrent
 	inline entry::list_type const& entry::list() const
 	{
 #ifndef BOOST_NO_EXCEPTIONS
-		if (m_type != list_t) throw type_error("invalid type requested from entry");
+		if (m_type != list_t) throw_type_error();
 #elif defined TORRENT_DEBUG
 		TORRENT_ASSERT(m_type_queried);
 #endif
@@ -313,7 +322,7 @@ namespace libtorrent
 	{
 		if (m_type == undefined_t) construct(dictionary_t);
 #ifndef BOOST_NO_EXCEPTIONS
-		if (m_type != dictionary_t) throw type_error("invalid type requested from entry");
+		if (m_type != dictionary_t) throw_type_error();
 #elif defined TORRENT_DEBUG
 		TORRENT_ASSERT(m_type_queried);
 #endif
@@ -324,7 +333,7 @@ namespace libtorrent
 	inline entry::dictionary_type const& entry::dict() const
 	{
 #ifndef BOOST_NO_EXCEPTIONS
-		if (m_type != dictionary_t) throw type_error("invalid type requested from entry");
+		if (m_type != dictionary_t) throw_type_error();
 #elif defined TORRENT_DEBUG
 		TORRENT_ASSERT(m_type_queried);
 #endif
diff --git a/include/libtorrent/error_code.hpp b/include/libtorrent/error_code.hpp
index 42d76e25a..1acb88e23 100644
--- a/include/libtorrent/error_code.hpp
+++ b/include/libtorrent/error_code.hpp
@@ -34,6 +34,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #define TORRENT_ERROR_CODE_HPP_INCLUDED
 
 #include <boost/version.hpp>
+#include <boost/shared_ptr.hpp>
 
 #if BOOST_VERSION < 103500
 #include <asio/error_code.hpp>
@@ -41,6 +42,8 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <boost/system/error_code.hpp>
 #endif
 
+#include "libtorrent/config.hpp"
+
 namespace libtorrent
 {
 
@@ -61,6 +64,15 @@ namespace libtorrent
 			torrent_file_parse_failed,
 			torrent_missing_pieces,
 			torrent_invalid_hashes,
+			too_many_pieces_in_torrent,
+			invalid_swarm_metadata,
+			invalid_bencoding,
+			no_files_in_torrent,
+			invalid_escaped_string,
+			session_is_closing,
+			duplicate_torrent,
+			invalid_torrent_handle,
+			invalid_entry_type,
 		};
 	}
 
@@ -70,7 +82,7 @@ namespace libtorrent
 	inline asio::error::error_category get_system_category() { return asio::error::system_category; }
 #else
 
-	struct libtorrent_error_category : boost::system::error_category
+	struct TORRENT_EXPORT libtorrent_error_category : boost::system::error_category
 	{
 		virtual const char* name() const;
 		virtual std::string message(int ev) const;
@@ -90,6 +102,23 @@ namespace libtorrent
 	{ return boost::system::get_generic_category(); }
 #endif
 #endif
+
+#ifndef BOOST_NO_EXCEPTIONS
+	struct TORRENT_EXPORT libtorrent_exception: std::exception
+	{
+		libtorrent_exception(error_code const& s): m_error(s) {}
+		virtual const char* what() const throw()
+		{
+			if (!m_msg) m_msg.reset(new std::string(m_error.message()));
+			return m_msg->c_str();
+		}
+		virtual ~libtorrent_exception() throw() {}
+		error_code error() const { return m_error; }
+	private:
+		error_code m_error;
+		mutable boost::shared_ptr<std::string> m_msg;
+	};
+#endif
 }
 
 #endif
diff --git a/include/libtorrent/escape_string.hpp b/include/libtorrent/escape_string.hpp
index f76939779..b40011ef8 100644
--- a/include/libtorrent/escape_string.hpp
+++ b/include/libtorrent/escape_string.hpp
@@ -39,6 +39,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <boost/array.hpp>
 #include "libtorrent/config.hpp"
 #include "libtorrent/size_type.hpp"
+#include "libtorrent/error_code.hpp"
 
 namespace libtorrent
 {
@@ -46,7 +47,7 @@ namespace libtorrent
 	bool TORRENT_EXPORT is_digit(char c);
 	bool TORRENT_EXPORT isprint(char c);
 
-	std::string TORRENT_EXPORT unescape_string(std::string const& s);
+	std::string TORRENT_EXPORT unescape_string(std::string const& s, error_code& ec);
 	std::string TORRENT_EXPORT escape_string(const char* str, int len);
 	std::string TORRENT_EXPORT escape_path(const char* str, int len);
 
diff --git a/include/libtorrent/session.hpp b/include/libtorrent/session.hpp
index d282167da..6421288a2 100644
--- a/include/libtorrent/session.hpp
+++ b/include/libtorrent/session.hpp
@@ -224,6 +224,7 @@ namespace libtorrent
 
 		// all torrent_handles must be destructed before the session is destructed!
 		torrent_handle add_torrent(add_torrent_params const& params);
+		torrent_handle add_torrent(add_torrent_params const& params, error_code& ec);
 		
 #ifndef TORRENT_NO_DEPRECATE
 		// deprecated in 0.14
diff --git a/include/libtorrent/torrent.hpp b/include/libtorrent/torrent.hpp
index 1dad5981e..7f9575d15 100644
--- a/include/libtorrent/torrent.hpp
+++ b/include/libtorrent/torrent.hpp
@@ -219,8 +219,8 @@ namespace libtorrent
 		void ip_filter_updated() { m_policy.ip_filter_updated(); }
 
 		void clear_error();
-		void set_error(std::string const& msg);
-		bool has_error() const { return !m_error.empty(); }
+		void set_error(error_code const& ec, std::string const& file);
+		bool has_error() const { return m_error; }
 		void pause();
 		void resume();
 
@@ -884,9 +884,10 @@ namespace libtorrent
 		// the state of this torrent (queued, checking, downloading)
 		torrent_status::state_t m_state;
 
-		// if there's an error on this torrent, this is the
-		// error message
-		std::string m_error;
+		// set if there's an error on this torrent
+		error_code m_error;
+		// if the error ocurred on a file, this is the file
+		std::string m_error_file;
 
 		// used if there is any resume data
 		std::vector<char> m_resume_data;
diff --git a/include/libtorrent/torrent_handle.hpp b/include/libtorrent/torrent_handle.hpp
index 64813221f..faade16f2 100644
--- a/include/libtorrent/torrent_handle.hpp
+++ b/include/libtorrent/torrent_handle.hpp
@@ -66,17 +66,12 @@ namespace libtorrent
 
 	struct torrent_plugin;
 
-	struct TORRENT_EXPORT duplicate_torrent: std::exception
-	{
-		virtual const char* what() const throw()
-		{ return "torrent already exists in session"; }
-	};
-
-	struct TORRENT_EXPORT invalid_handle: std::exception
-	{
-		virtual const char* what() const throw()
-		{ return "invalid torrent handle used"; }
-	};
+#ifndef BOOST_NO_EXCEPTIONS
+	// for compatibility with 0.14
+	typedef libtorrent_exception duplicate_torrent;
+	typedef libtorrent_exception invalid_handle;
+	void throw_invalid_handle();
+#endif
 
 	struct TORRENT_EXPORT torrent_status
 	{
diff --git a/include/libtorrent/torrent_info.hpp b/include/libtorrent/torrent_info.hpp
index b2fffe037..ad250ab5f 100644
--- a/include/libtorrent/torrent_info.hpp
+++ b/include/libtorrent/torrent_info.hpp
@@ -155,13 +155,8 @@ namespace libtorrent
 	};
 
 #ifndef BOOST_NO_EXCEPTIONS
-	struct TORRENT_EXPORT invalid_torrent_file: std::exception
-	{
-		invalid_torrent_file(std::string const& s): m_error(s) {}
-		virtual const char* what() const throw() { return m_error.c_str(); }
-		virtual ~invalid_torrent_file() throw() {}
-		std::string m_error;
-	};
+	// for backwards compatibility with 0.14
+	typedef libtorrent_exception invalid_torrent_file;
 #endif
 
 	int TORRENT_EXPORT load_file(fs::path const& filename, std::vector<char>& v);
@@ -169,12 +164,20 @@ namespace libtorrent
 	class TORRENT_EXPORT torrent_info : public intrusive_ptr_base<torrent_info>
 	{
 	public:
-
+#ifndef BOOST_NO_EXCEPTIONS
 		torrent_info(sha1_hash const& info_hash);
 		torrent_info(lazy_entry const& torrent_file);
 		torrent_info(char const* buffer, int size);
 		torrent_info(fs::path const& filename);
 		torrent_info(fs::wpath const& filename);
+#endif
+
+		torrent_info(sha1_hash const& info_hash, error_code& ec);
+		torrent_info(lazy_entry const& torrent_file, error_code& ec);
+		torrent_info(char const* buffer, int size, error_code& ec);
+		torrent_info(fs::path const& filename, error_code& ec);
+		torrent_info(fs::wpath const& filename, error_code& ec);
+
 		~torrent_info();
 
 		file_storage const& files() const { return m_files; }
diff --git a/src/create_torrent.cpp b/src/create_torrent.cpp
index 3a980c368..d099c7a77 100644
--- a/src/create_torrent.cpp
+++ b/src/create_torrent.cpp
@@ -170,15 +170,11 @@ namespace libtorrent
 	{
 		TORRENT_ASSERT(m_files.piece_length() > 0);
 
-		if (m_files.num_files() == 0)
-		{
-			// TODO: throw something here
-			// throw
-			return entry();
-		}
-
 		entry dict;
 
+		if (m_files.num_files() == 0)
+			return dict;
+
 		if (!m_urls.empty()) dict["announce"] = m_urls.front().first;
 		
 		if (!m_nodes.empty())
diff --git a/src/error_code.cpp b/src/error_code.cpp
index fee33946e..339965971 100644
--- a/src/error_code.cpp
+++ b/src/error_code.cpp
@@ -60,6 +60,15 @@ namespace libtorrent
 			"failed to parse files from torrent file",
 			"invalid or missing 'pieces' entry in torrent file",
 			"incorrect number of piece hashes in torrent file",
+			"too many pieces in torrent",
+			"invalid metadata received from swarm",
+			"invalid bencoding",
+			"no files in torrent",
+			"invalid escaped string",
+			"session is closing",
+			"torrent already exists in session",
+			"invalid torrent handle used",
+			"invalid type requested from entry",
 		};
 		if (ev < 0 || ev >= sizeof(msgs)/sizeof(msgs[0]))
 			return "Unknown error";
diff --git a/src/escape_string.cpp b/src/escape_string.cpp
index 39c02a9a6..5abc3f58f 100644
--- a/src/escape_string.cpp
+++ b/src/escape_string.cpp
@@ -79,7 +79,7 @@ namespace libtorrent
 		return c >= 32 && c < 127;
 	}
 
-	std::string unescape_string(std::string const& s)
+	std::string unescape_string(std::string const& s, error_code& ec)
 	{
 		std::string ret;
 		for (std::string::const_iterator i = s.begin(); i != s.end(); ++i)
@@ -96,41 +96,37 @@ namespace libtorrent
 			{
 				++i;
 				if (i == s.end())
-#ifdef BOOST_NO_EXCEPTIONS
+				{
+					ec = error_code(errors::invalid_escaped_string, libtorrent_category);
 					return ret;
-#else
-					throw std::runtime_error("invalid escaped string");
-#endif
+				}
 
 				int high;
 				if(*i >= '0' && *i <= '9') high = *i - '0';
 				else if(*i >= 'A' && *i <= 'F') high = *i + 10 - 'A';
 				else if(*i >= 'a' && *i <= 'f') high = *i + 10 - 'a';
 				else
-#ifdef BOOST_NO_EXCEPTIONS
+				{
+					ec = error_code(errors::invalid_escaped_string, libtorrent_category);
 					return ret;
-#else
-					throw std::runtime_error("invalid escaped string");
-#endif
+				}
 
 				++i;
 				if (i == s.end())
-#ifdef BOOST_NO_EXCEPTIONS
+				{
+					ec = error_code(errors::invalid_escaped_string, libtorrent_category);
 					return ret;
-#else
-					throw std::runtime_error("invalid escaped string");
-#endif
+				}
 
 				int low;
 				if(*i >= '0' && *i <= '9') low = *i - '0';
 				else if(*i >= 'A' && *i <= 'F') low = *i + 10 - 'A';
 				else if(*i >= 'a' && *i <= 'f') low = *i + 10 - 'a';
 				else
-#ifdef BOOST_NO_EXCEPTIONS
+				{
+					ec = error_code(errors::invalid_escaped_string, libtorrent_category);
 					return ret;
-#else
-					throw std::runtime_error("invalid escaped string");
-#endif
+				}
 
 				ret += char(high * 16 + low);
 			}
diff --git a/src/magnet_uri.cpp b/src/magnet_uri.cpp
index 2570afc83..28a94daff 100644
--- a/src/magnet_uri.cpp
+++ b/src/magnet_uri.cpp
@@ -100,10 +100,11 @@ namespace libtorrent
 		std::string name;
 		std::string tracker;
 
+		error_code ec;
 		boost::optional<std::string> display_name = url_has_argument(uri, "dn");
-		if (display_name) name = unescape_string(display_name->c_str());
+		if (display_name) name = unescape_string(display_name->c_str(), ec);
 		boost::optional<std::string> tracker_string = url_has_argument(uri, "tr");
-		if (tracker_string) tracker = unescape_string(tracker_string->c_str());
+		if (tracker_string) tracker = unescape_string(tracker_string->c_str(), ec);
 	
 		boost::optional<std::string> btih = url_has_argument(uri, "xt");
 		if (!btih) return torrent_handle();
@@ -124,10 +125,11 @@ namespace libtorrent
 		std::string name;
 		std::string tracker;
 
+		error_code ec;
 		boost::optional<std::string> display_name = url_has_argument(uri, "dn");
-		if (display_name) name = unescape_string(display_name->c_str());
+		if (display_name) name = unescape_string(display_name->c_str(), ec);
 		boost::optional<std::string> tracker_string = url_has_argument(uri, "tr");
-		if (tracker_string) tracker = unescape_string(tracker_string->c_str());
+		if (tracker_string) tracker = unescape_string(tracker_string->c_str(), ec);
 	
 		boost::optional<std::string> btih = url_has_argument(uri, "xt");
 		if (!btih) return torrent_handle();
diff --git a/src/peer_connection.cpp b/src/peer_connection.cpp
index 2e86ce972..4fecde276 100644
--- a/src/peer_connection.cpp
+++ b/src/peer_connection.cpp
@@ -1965,7 +1965,7 @@ namespace libtorrent
 		
 			if (t->alerts().should_post<file_error_alert>())
 				t->alerts().post_alert(file_error_alert(j.error_file, t->get_handle(), j.str));
-			t->set_error(j.str);
+			t->set_error(j.error, j.error_file);
 			t->pause();
 			return;
 		}
@@ -3313,7 +3313,7 @@ namespace libtorrent
 			{
 				if (t->alerts().should_post<file_error_alert>())
 					t->alerts().post_alert(file_error_alert(j.error_file, t->get_handle(), j.str));
-				t->set_error(j.str);
+				t->set_error(j.error, j.error_file);
 				t->pause();
 			}
 			return;
@@ -3681,7 +3681,6 @@ namespace libtorrent
 	// RECEIVE DATA
 	// --------------------------
 
-	// throws exception when the client should be disconnected
 	void peer_connection::on_receive_data(const error_code& error
 		, std::size_t bytes_transferred)
 	{
@@ -3976,7 +3975,6 @@ namespace libtorrent
 	// SEND DATA
 	// --------------------------
 
-	// throws exception when the client should be disconnected
 	void peer_connection::on_send_data(error_code const& error
 		, std::size_t bytes_transferred)
 	{
diff --git a/src/session.cpp b/src/session.cpp
index a0b239d8a..77bf2c609 100644
--- a/src/session.cpp
+++ b/src/session.cpp
@@ -298,9 +298,19 @@ namespace libtorrent
 		return m_impl->find_torrent_handle(info_hash);
 	}
 
+#ifndef BOOST_NO_EXCEPTIONS
 	torrent_handle session::add_torrent(add_torrent_params const& params)
 	{
-		return m_impl->add_torrent(params);
+		error_code ec;
+		torrent_handle ret = m_impl->add_torrent(params, ec);
+		if (ec) throw libtorrent_exception(ec);
+		return ret;
+	}
+#endif
+
+	torrent_handle session::add_torrent(add_torrent_params const& params, error_code& ec)
+	{
+		return m_impl->add_torrent(params, ec);
 	}
 
 #ifndef TORRENT_NO_DEPRECATE
@@ -325,7 +335,7 @@ namespace libtorrent
 		}
 		p.storage_mode = storage_mode;
 		p.paused = paused;
-		return m_impl->add_torrent(p);
+		return add_torrent(p);
 	}
 
 	torrent_handle session::add_torrent(
@@ -349,7 +359,7 @@ namespace libtorrent
 		p.storage_mode = storage_mode;
 		p.paused = paused;
 		p.userdata = userdata;
-		return m_impl->add_torrent(p);
+		return add_torrent(p);
 	}
 
 	torrent_handle session::add_torrent(
@@ -369,7 +379,7 @@ namespace libtorrent
 		p.save_path = save_path;
 		p.paused = paused;
 		p.userdata = userdata;
-		return m_impl->add_torrent(p);
+		return add_torrent(p);
 	}
 #endif
 
diff --git a/src/session_impl.cpp b/src/session_impl.cpp
index d1e4eda01..0bc1717d2 100644
--- a/src/session_impl.cpp
+++ b/src/session_impl.cpp
@@ -1837,17 +1837,15 @@ namespace aux {
 		return torrent_handle(find_torrent(info_hash));
 	}
 
-	torrent_handle session_impl::add_torrent(add_torrent_params const& params)
+	torrent_handle session_impl::add_torrent(add_torrent_params const& params
+		, error_code& ec)
 	{
 		TORRENT_ASSERT(!params.save_path.empty());
 
 		if (params.ti && params.ti->num_files() == 0)
 		{
-#ifndef BOOST_NO_EXCEPTIONS
-			throw std::runtime_error("no files in torrent");
-#else
+			ec = error_code(errors::no_files_in_torrent, libtorrent_category);
 			return torrent_handle();
-#endif
 		}
 
 		// lock the session and the checker thread (the order is important!)
@@ -1857,11 +1855,8 @@ namespace aux {
 
 		if (is_aborted())
 		{
-#ifndef BOOST_NO_EXCEPTIONS
-			throw std::runtime_error("session is closing");
-#else
+			ec = error_code(errors::session_is_closing, libtorrent_category);
 			return torrent_handle();
-#endif
 		}
 		
 		// figure out the info hash of the torrent
@@ -1876,11 +1871,8 @@ namespace aux {
 			if (!params.duplicate_is_error)
 				return torrent_handle(torrent_ptr);
 
-#ifndef BOOST_NO_EXCEPTIONS
-			throw duplicate_torrent();
-#else
+			ec = error_code(errors::duplicate_torrent, libtorrent_category);
 			return torrent_handle();
-#endif
 		}
 
 		int queue_pos = 0;
@@ -1967,7 +1959,7 @@ namespace aux {
 #ifdef BOOST_NO_EXCEPTIONS
 			return;
 #else
-			throw invalid_handle();
+			throw_invalid_handle();
 #endif
 
 		mutex_t::scoped_lock l(m_mutex);
diff --git a/src/torrent.cpp b/src/torrent.cpp
index 367d74580..2132ecf43 100644
--- a/src/torrent.cpp
+++ b/src/torrent.cpp
@@ -344,7 +344,7 @@ namespace libtorrent
 		if (ret != r.length)
 		{
 			rp->fail = true;
-			set_error(j.str);
+			set_error(j.error, j.error_file);
 			pause();
 		}
 		else
@@ -425,7 +425,7 @@ namespace libtorrent
 			if (has_picker()) picker().write_failed(block_finished);
 			if (alerts().should_post<file_error_alert>())
 				alerts().post_alert(file_error_alert(j.error_file, get_handle(), j.str));
-			set_error(j.str);
+			set_error(j.error, j.error_file);
 			pause();
 			return;
 		}
@@ -504,10 +504,9 @@ namespace libtorrent
 
 		m_block_size = (std::min)(m_block_size, m_torrent_file->piece_length());
 
-		if (m_torrent_file->num_pieces()
-			> piece_picker::max_pieces)
+		if (m_torrent_file->num_pieces() > piece_picker::max_pieces)
 		{
-			set_error("too many pieces in torrent");
+			set_error(error_code(errors::too_many_pieces_in_torrent, libtorrent_category), "");
 			pause();
 		}
 
@@ -621,7 +620,7 @@ namespace libtorrent
 				" torrent: " << torrent_file().name() <<
 				" ]\n";
 #endif
-			set_error(j.str);
+			set_error(j.error, j.error_file);
 			pause();
 			set_state(torrent_status::queued_for_checking);
 
@@ -790,7 +789,7 @@ namespace libtorrent
 			set_state(torrent_status::queued_for_checking);
 			return;
 		}
-		if (!m_error.empty()) m_error.clear();
+		clear_error();
 
 		disconnect_all();
 
@@ -832,7 +831,7 @@ namespace libtorrent
 				" torrent: " << torrent_file().name() <<
 				" ]\n";
 #endif
-			set_error(j.str);
+			set_error(j.error, j.error_file);
 			pause();
 			return;
 		}
@@ -874,7 +873,7 @@ namespace libtorrent
 				" ]\n";
 #endif
 			pause();
-			set_error(j.str);
+			set_error(j.error, j.error_file);
 			return;
 		}
 
@@ -3427,7 +3426,7 @@ namespace libtorrent
 			{
 				alerts().post_alert(metadata_failed_alert(get_handle()));
 			}
-			set_error("invalid metadata: " + ec.message());
+			set_error(error_code(errors::invalid_swarm_metadata, libtorrent_category), "");
 			pause();
 			return false;
 		}
@@ -4297,19 +4296,21 @@ namespace libtorrent
 
 	void torrent::clear_error()
 	{
-		if (m_error.empty()) return;
+		if (!m_error) return;
 		bool checking_files = should_check_files();
 		if (m_ses.m_auto_manage_time_scaler > 2)
 			m_ses.m_auto_manage_time_scaler = 2;
-		m_error.clear();
+		m_error = error_code();
+		m_error_file.clear();
 		if (!checking_files && should_check_files())
 			queue_torrent_check();
 	}
 
-	void torrent::set_error(std::string const& msg)
+	void torrent::set_error(error_code const& ec, std::string const& error_file)
 	{
 		bool checking_files = should_check_files();
-		m_error = msg;
+		m_error = ec;
+		m_error_file = error_file;
 		if (checking_files && !should_check_files())
 		{
 			// stop checking
@@ -4441,7 +4442,7 @@ namespace libtorrent
 		return (m_state == torrent_status::checking_files
 			|| m_state == torrent_status::queued_for_checking)
 			&& (!m_paused || m_auto_managed)
-			&& m_error.empty()
+			&& !has_error()
 			&& !m_abort;
 	}
 
@@ -4547,7 +4548,7 @@ namespace libtorrent
 			alerts().post_alert(torrent_resumed_alert(get_handle()));
 
 		m_started = time_now();
-		m_error.clear();
+		clear_error();
 		start_announcing();
 	}
 
@@ -4830,7 +4831,7 @@ namespace libtorrent
 		{
 			if (alerts().should_post<file_error_alert>())
 				alerts().post_alert(file_error_alert(j.error_file, get_handle(), j.str));
-			set_error(j.str);
+			set_error(j.error, j.error_file);
 			pause();
 		}
 		f(ret);
@@ -5028,7 +5029,7 @@ namespace libtorrent
 		torrent_status st;
 
 		st.has_incoming = m_has_incoming;
-		st.error = m_error;
+		if (m_error) st.error = m_error.message() + ": " + m_error_file;
 		st.seed_mode = m_seed_mode;
 
 		if (m_last_scrape == min_time())
diff --git a/src/torrent_handle.cpp b/src/torrent_handle.cpp
index 6fd246787..cb8120efb 100644
--- a/src/torrent_handle.cpp
+++ b/src/torrent_handle.cpp
@@ -123,15 +123,13 @@ namespace libtorrent
 {
 	namespace fs = boost::filesystem;
 
-	namespace
-	{
 #ifndef BOOST_NO_EXCEPTIONS
-		void throw_invalid_handle()
-		{
-			throw invalid_handle();
-		}
-#endif
+	void throw_invalid_handle()
+	{
+		throw libtorrent_exception(error_code(
+			errors::invalid_torrent_handle, libtorrent_category));
 	}
+#endif
 
 #ifdef TORRENT_DEBUG
 
diff --git a/src/torrent_info.cpp b/src/torrent_info.cpp
index f807f0e1b..0701821e3 100644
--- a/src/torrent_info.cpp
+++ b/src/torrent_info.cpp
@@ -291,17 +291,25 @@ namespace libtorrent
 		bencode(out, torrent_file);
 
 		lazy_entry e;
-		lazy_bdecode(&tmp[0], &tmp[0] + tmp.size(), e);
+		if (lazy_bdecode(&tmp[0], &tmp[0] + tmp.size(), e) != 0)
+		{
+#ifndef BOOST_NO_EXCEPTIONS
+			throw invalid_torrent_file(error_code(
+				errors::invalid_bencoding, libtorrent_category));
+#endif
+			return;
+		}
 		error_code ec;
 #ifndef BOOST_NO_EXCEPTIONS
 		if (!parse_torrent_file(e, ec))
-			throw invalid_torrent_file(ec.message());
+			throw invalid_torrent_file(ec);
 #else
 		parse_torrent_file(e, ec);
 #endif
 	}
 #endif
 
+#ifndef BOOST_NO_EXCEPTIONS
 	torrent_info::torrent_info(lazy_entry const& torrent_file)
 		: m_creation_date(pt::ptime(pt::not_a_date_time))
 		, m_multifile(false)
@@ -310,12 +318,8 @@ namespace libtorrent
 		, m_piece_hashes(0)
 	{
 		error_code ec;
-#ifndef BOOST_NO_EXCEPTIONS
 		if (!parse_torrent_file(torrent_file, ec))
-			throw invalid_torrent_file(ec.message());
-#else
-		parse_torrent_file(torrent_file, ec);
-#endif
+			throw invalid_torrent_file(ec);
 	}
 
 	torrent_info::torrent_info(char const* buffer, int size)
@@ -327,13 +331,124 @@ namespace libtorrent
 	{
 		error_code ec;
 		lazy_entry e;
-		lazy_bdecode(buffer, buffer + size, e);
-#ifndef BOOST_NO_EXCEPTIONS
+		if (lazy_bdecode(buffer, buffer + size, e) != 0)
+			throw invalid_torrent_file(error_code(
+				errors::invalid_bencoding, libtorrent_category));
+
 		if (!parse_torrent_file(e, ec))
-			throw invalid_torrent_file(ec.message());
-#else
-		parse_torrent_file(e, ec);
+			throw invalid_torrent_file(ec);
+	}
+
+	torrent_info::torrent_info(fs::path const& filename)
+		: m_creation_date(pt::ptime(pt::not_a_date_time))
+		, m_multifile(false)
+		, m_private(false)
+		, m_info_section_size(0)
+		, m_piece_hashes(0)
+	{
+		std::vector<char> buf;
+		int ret = load_file(filename, buf);
+		if (ret < 0) return;
+
+		lazy_entry e;
+		if (lazy_bdecode(&buf[0], &buf[0] + buf.size(), e) != 0)
+			throw invalid_torrent_file(error_code(
+				errors::invalid_bencoding, libtorrent_category));
+		error_code ec;
+		if (!parse_torrent_file(e, ec))
+			throw invalid_torrent_file(ec);
+	}
+
+	torrent_info::torrent_info(fs::wpath const& filename)
+		: m_creation_date(pt::ptime(pt::not_a_date_time))
+		, m_multifile(false)
+		, m_private(false)
+		, m_info_section_size(0)
+		, m_piece_hashes(0)
+	{
+		std::vector<char> buf;
+		std::string utf8;
+		wchar_utf8(filename.string(), utf8);
+		int ret = load_file(utf8, buf);
+		if (ret < 0) return;
+
+		lazy_entry e;
+		if (lazy_bdecode(&buf[0], &buf[0] + buf.size(), e) != 0)
+			throw invalid_torrent_file(error_code(
+				errors::invalid_bencoding, libtorrent_category));
+
+		error_code ec;
+		if (!parse_torrent_file(e, ec))
+			throw invalid_torrent_file(ec);
+	}
 #endif
+
+	torrent_info::torrent_info(lazy_entry const& torrent_file, error_code& ec)
+		: m_creation_date(pt::ptime(pt::not_a_date_time))
+		, m_multifile(false)
+		, m_private(false)
+		, m_info_section_size(0)
+		, m_piece_hashes(0)
+	{
+		parse_torrent_file(torrent_file, ec);
+	}
+
+	torrent_info::torrent_info(char const* buffer, int size, error_code& ec)
+		: m_creation_date(pt::ptime(pt::not_a_date_time))
+		, m_multifile(false)
+		, m_private(false)
+		, m_info_section_size(0)
+		, m_piece_hashes(0)
+	{
+		lazy_entry e;
+		if (lazy_bdecode(buffer, buffer + size, e) != 0)
+		{
+			ec = error_code(errors::invalid_bencoding, libtorrent_category);
+			return;
+		}
+		parse_torrent_file(e, ec);
+	}
+
+	torrent_info::torrent_info(fs::path const& filename, error_code& ec)
+		: m_creation_date(pt::ptime(pt::not_a_date_time))
+		, m_multifile(false)
+		, m_private(false)
+		, m_info_section_size(0)
+		, m_piece_hashes(0)
+	{
+		std::vector<char> buf;
+		int ret = load_file(filename, buf);
+		if (ret < 0) return;
+
+		lazy_entry e;
+		if (lazy_bdecode(&buf[0], &buf[0] + buf.size(), e) != 0)
+		{
+			ec = error_code(errors::invalid_bencoding, libtorrent_category);
+			return;
+		}
+		parse_torrent_file(e, ec);
+	}
+
+	torrent_info::torrent_info(fs::wpath const& filename, error_code& ec)
+		: m_creation_date(pt::ptime(pt::not_a_date_time))
+		, m_multifile(false)
+		, m_private(false)
+		, m_info_section_size(0)
+		, m_piece_hashes(0)
+	{
+		std::vector<char> buf;
+		std::string utf8;
+		wchar_utf8(filename.string(), utf8);
+		int ret = load_file(utf8, buf);
+		if (ret < 0) return;
+
+		lazy_entry e;
+		if (lazy_bdecode(&buf[0], &buf[0] + buf.size(), e) != 0)
+		{
+			ec = error_code(errors::invalid_bencoding, libtorrent_category);
+			return;
+		}
+		parse_torrent_file(e, ec);
 	}
 
 	// constructor used for creating new torrents
@@ -349,62 +464,6 @@ namespace libtorrent
 		, m_piece_hashes(0)
 	{}
 
-	torrent_info::torrent_info(fs::path const& filename)
-		: m_creation_date(pt::ptime(pt::not_a_date_time))
-		, m_multifile(false)
-		, m_private(false)
-	{
-		std::vector<char> buf;
-		int ret = load_file(filename, buf);
-		if (ret < 0) return;
-
-		if (buf.empty())
-#ifndef BOOST_NO_EXCEPTIONS
-			throw invalid_torrent_file("file not found");
-#else
-			return;
-#endif
-
-		lazy_entry e;
-		lazy_bdecode(&buf[0], &buf[0] + buf.size(), e);
-		error_code ec;
-#ifndef BOOST_NO_EXCEPTIONS
-		if (!parse_torrent_file(e, ec))
-			throw invalid_torrent_file(ec.message());
-#else
-		parse_torrent_file(e, ec);
-#endif
-	}
-
-	torrent_info::torrent_info(fs::wpath const& filename)
-		: m_creation_date(pt::ptime(pt::not_a_date_time))
-		, m_multifile(false)
-		, m_private(false)
-	{
-		std::vector<char> buf;
-		std::string utf8;
-		wchar_utf8(filename.string(), utf8);
-		int ret = load_file(utf8, buf);
-		if (ret < 0) return;
-
-		if (buf.empty())
-#ifndef BOOST_NO_EXCEPTIONS
-			throw invalid_torrent_file("empty file");
-#else
-			return;
-#endif
-
-		lazy_entry e;
-		lazy_bdecode(&buf[0], &buf[0] + buf.size(), e);
-		error_code ec;
-#ifndef BOOST_NO_EXCEPTIONS
-		if (!parse_torrent_file(e, ec))
-			throw invalid_torrent_file(ec.message());
-#else
-		parse_torrent_file(e, ec);
-#endif
-	}
-
 	torrent_info::~torrent_info()
 	{}