crypto/...: more fixes for bug 2841

1) Remove the Reset() member in crypto/aes and crypto/des (and
   document the change).
2) Turn several empty error structures into vars. Any remaining error
   structures are either non-empty, or will probably become so in the
   future.
3) Implement SetWriteDeadline for TLS sockets. At the moment, the TLS
   status cannot be reused after a Write error, which is probably fine
   for most uses.
4) Make crypto/aes and crypto/des return a cipher.Block.

R=rsc, r
CC=golang-dev
https://golang.org/cl/5625045

doc/go1.html

@@ -855,38 +855,23 @@ few programs beyond the need to run <code>go fix</code>.
 This category includes packages that are new in Go 1.
 </p>
 
-<h3 id="bufio">The bufio package</h3>
+<h3 id="crypto_aes_des">The crypto/aes and crypto/des packages</h3>
 
 <p>
-In Go 1, <a href="/pkg/bufio/#NewReaderSize"><code>bufio.NewReaderSize</code></a>
+In Go 1, the <code>Reset</code> method has been removed. Go does not guarantee
-and
+that memory is not copied and therefore this method was misleading.
-<a href="/pkg/bufio/#NewWriterSize"><code>bufio.NewWriterSize</code></a>
+</p>
-functions no longer return an error for invalid sizes.
+
-If the argument size is too small or invalid, it is adjusted.
+<p>
+The cipher-specific types <code>*aes.Cipher</code>, <code>*des.Cipher</code>,
+and <code>*des.TripleDESCipher</code> have been removed in favor of
+<code>cipher.Block</code>.
 </p>
 
 <p>
 <em>Updating</em>:
-What little code is affected will be caught by the compiler and must be updated by hand.
+Remove the calls to Reset. Replace uses of the specific cipher types with
-</p>
+cipher.Block.
-
-<h3 id="bufio">The compress/flate, compress/gzip and compress/zlib packages</h3>
-
-<p>
-In Go 1, the <code>NewWriterXxx</code> functions in
-<a href="/pkg/compress/flate"><code>compress/flate</code></a>,
-<a href="/pkg/compress/gzip"><code>compress/gzip</code></a> and
-<a href="/pkg/compress/zlib"><code>compress/zlib</code></a>
-all return <code>(*Writer, error)</code> if they take a compression level,
-and <code>*Writer</code> otherwise. Package <code>gzip</code>'s
-<code>Compressor</code> and <code>Decompressor</code> types have been renamed
-to <code>Writer</code> and <code>Reader</code>. Package <code>flate</code>'s
-<code>WrongValueError</code> type has been removed.
-</p>
-
-<p>
-<em>Updating</em>:
-What little code is affected will be caught by the compiler and must be updated by hand.
 </p>
 
 <h3 id="crypto_elliptic">The crypto/elliptic package</h3>
@@ -939,64 +924,6 @@ to be implemented in the future.
 No changes will be needed.
 </p>
 
-<h3 id="encoding_binary">The encoding/binary package</h3>
-
-<p>
-In Go 1, the <code>binary.TotalSize</code> function has been replaced by
-<a href="/pkg/encoding/binary/#Size"><code>Size</code></a>,
-which takes an <code>interface{}</code> argument rather than
-a <code>reflect.Value</code>.
-</p>
-
-<p>
-<em>Updating</em>:
-What little code is affected will be caught by the compiler and must be updated by hand.
-</p>
-
-<h3 id="encoding_xml">The encoding/xml package</h3>
-
-<p>
-In Go 1, the <a href="/pkg/encoding/xml/"><code>xml</code></a> package
-has been brought closer in design to the other marshaling packages such
-as <a href="/pkg/encoding/gob/"><code>encoding/gob</code></a>.
-</p>
-
-<p>
-The old <code>Parser</code> type is renamed
-<a href="/pkg/encoding/xml/#Decoder"><code>Decoder</code></a> and has a new
-<a href="/pkg/encoding/xml/#Decoder.Decode"><code>Decode</code></a> method. An
-<a href="/pkg/encoding/xml/#Encoder"><code>Encoder</code></a> type was also
-introduced.
-</p>
-
-<p>
-The functions <a href="/pkg/encoding/xml/#Marshal"><code>Marshal</code></a>
-and <a href="/pkg/encoding/xml/#Unmarshal"><code>Unmarshal</code></a>
-work with <code>[]byte</code> values now. To work with streams,
-use the new <a href="/pkg/encoding/xml/#Encoder"><code>Encoder</code></a>
-and <a href="/pkg/encoding/xml/#Decoder"><code>Decoder</code></a> types.
-</p>
-
-<p>
-When marshaling or unmarshaling values, the format of supported flags in
-field tags has changed to be closer to the
-<a href="/pkg/encoding/json"><code>json</code></a> package
-(<code>`xml:"name,flag"`</code>). The matching done between field tags, field
-names, and the XML attribute and element names is now case-sensitive.
-The <code>XMLName</code> field tag, if present, must also match the name
-of the XML element being marshaled.
-</p>
-
-<p>
-<em>Updating</em>:
-Running <code>go fix</code> will update most uses of the package except for some calls to
-<code>Unmarshal</code>. Special care must be taken with field tags,
-since the fix tool will not update them and if not fixed by hand they will
-misbehave silently in some cases. For example, the old
-<code>"attr"</code> is now written <code>",attr"</code> while plain
-<code>"attr"</code> remains valid but with a different meaning.
-</p>
-
 <h3 id="expvar">The expvar package</h3>
 
 <p>
@@ -1046,15 +973,6 @@ The <code>Duration</code> flag is new and affects no existing code.
 Several packages under <code>go</code> have slightly revised APIs.
 </p>
 
-<p>
-A concrete <code>Mode</code> type was introduced for configuration mode flags
-in the packages
-<a href="/pkg/go/scanner/"><code>go/scanner</code></a>,
-<a href="/pkg/go/parser/"><code>go/parser</code></a>,
-<a href="/pkg/go/printer/"><code>go/printer</code></a>, and
-<a href="/pkg/go/doc/"><code>go/doc</code></a>.
-</p>
-
 <p>
 The modes <code>AllowIllegalChars</code> and <code>InsertSemis</code> have been removed
 from the <a href="/pkg/go/scanner/"><code>go/scanner</code></a> package. They were mostly
@@ -1063,16 +981,6 @@ useful for scanning text other then Go source files. Instead, the
 for that purpose.
 </p>
 
-<p>
-The <a href="/pkg/go/scanner/#ErrorHandler"><code>ErrorHandler</code></a> provided
-to the scanner's <a href="/pkg/go/scanner/#Scanner.Init"><code>Init</code></a> method is
-now simply a function rather than an interface. The <code>ErrorVector</code> type has
-been removed in favor of the (existing) <a href="/pkg/go/scanner/#ErrorList"><code>ErrorList</code></a>
-type, and the <code>ErrorVector</code> methods have been migrated. Instead of embedding
-an <code>ErrorVector</code> in a client of the scanner, now a client should maintain
-an <code>ErrorList</code>.
-</p>
-
 <p>
 The set of parse functions provided by the <a href="/pkg/go/parser/"><code>go/parser</code></a>
 package has been reduced to the primary parse function
@@ -1081,17 +989,6 @@ convenience functions <a href="/pkg/go/parser/#ParseDir"><code>ParseDir</code></
 and <a href="/pkg/go/parser/#ParseExpr"><code>ParseExpr</code></a>.
 </p>
 
-<p>
-The <a href="/pkg/go/printer/"><code>go/printer</code></a> package supports an additional
-configuration mode <a href="/pkg/go/printer/#Mode"><code>SourcePos</code></a>;
-if set, the printer will emit <code>//line</code> comments such that the generated
-output contains the original source code position information. The new type
-<a href="/pkg/go/printer/#CommentedNode"><code>CommentedNode</code></a> can be
-used to provide comments associated with an arbitrary
-<a href="/pkg/go/ast/#Node"><code>ast.Node</code></a> (until now only
-<a href="/pkg/go/ast/#File"><code>ast.File</code></a> carried comment information).
-</p>
-
 <p>
 The type names of the <a href="/pkg/go/doc/"><code>go/doc</code></a> package have been
 streamlined by removing the <code>Doc</code> suffix: <code>PackageDoc</code>
@@ -1189,16 +1086,10 @@ The affected items are:
 </ul>
 
 <p>
-The <code>Request.RawURL</code> field has been removed; it was a
+Also, the <code>Request.RawURL</code> field has been removed; it was a
 historical artifact.
 </p>
 
-<p>
-The <code>Handle</code> and <code>HandleFunc</code>
-functions, and the similarly-named methods of <code>ServeMux</code>,
-now panic if an attempt is made to register the same pattern twice.
-</p>
-
 <p>
 <em>Updating</em>:
 Running <code>go fix</code> will update the few programs that are affected except for
@@ -1235,7 +1126,9 @@ packages.
 The old <code>image.ColorImage</code> type is still in the <code>image</code>
 package but has been renamed
 <a href="/pkg/image/#Uniform"><code>image.Uniform</code></a>,
-while <code>image.Tiled</code> has been removed.
+while <code>image.Tiled</code>
+has been renamed
+<a href="/pkg/image/#Repeated"><code>image.Repeated</code></a>.
 </p>
 
 <p>
@@ -1296,6 +1189,7 @@ This table lists the renamings.
 <td colspan="2"><hr></td>
 </tr>
 <tr><td>image.ColorImage</td> <td>image.Uniform</td></tr>
+<tr><td>image.Tiled</td> <td>image.Repeated</td></tr>
 </table>
 
 <p>
@@ -1320,18 +1214,6 @@ and
 Running <code>go fix</code> will update almost all code affected by the change.
 </p>
 
-<h3 id="log_syslog">The log/syslog package</h3>
-
-<p>
-In Go 1, the <a href="/pkg/log/syslog/#NewLogger"><code>syslog.NewLogger</code></a>
-function returns an error as well as a <code>log.Logger</code>.
-</p>
-
-<p>
-<em>Updating</em>:
-What little code is affected will be caught by the compiler and must be updated by hand.
-</p>
-
 <h3 id="mime">The mime package</h3>
 
 <p>
@@ -1378,27 +1260,7 @@ Code that uses the old methods will fail to compile and must be updated by hand.
 The semantic change makes it difficult for the fix tool to update automatically.
 </p>
 
-<h3 id="os">The os package</h3>
+<h3 id="os_fileinfo">The os.FileInfo type</h3>
-
-<p>The <code>Time</code> function has been removed; callers should use
-the <a href="/pkg/time/#Time"><code>Time</code></a> type from the
-<code>time</code> package.</p>
-
-<p>The <code>Exec</code> function has been removed; callers should use
-<code>Exec</code> from the <code>syscall</code> package, where available.</p>
-
-<p>The <code>ShellExpand</code> function has been renamed to <a
-href="/pkg/os/#ExpandEnv"><code>ExpandEnv</code></a>.</p>
-
-<p>The <a href="/pkg/os/#NewFile"><code>NewFile</code></a> function
-now takes a <code>uintptr</code> fd, instead of an <code>int</code>.
-The <a href="/pkg/os/#File.Fd"><code>Fd</code></a> method on files now
-also returns a <code>uintptr</code>.</p>
-
-<p><em>Updating</em>: Code will fail to compile and must be updated
-by hand.  </p>
-
-<h4 id="os_fileinfo">The os.FileInfo type</h4>
 
 <p>
 Go 1 redefines the <a href="/pkg/os/#FileInfo"><code>os.FileInfo</code></a> type,
@@ -1639,17 +1501,6 @@ Existing code is unaffected, although benchmarks that use <code>println</code>
 or <code>panic</code> should be updated to use the new methods.
 </p>
 
-<h3 id="testing_script">The testing/script package</h3>
-
-<p>
-The testing/script package has been deleted. It was a dreg.
-</p>
-
-<p>
-<em>Updating</em>:
-No code is likely to be affected.
-</p>
-
 <h3 id="url">The url package</h3>
 
 <p>
@@ -1718,6 +1569,50 @@ Code that uses the old fields will fail to compile and must be updated by hand.
 The semantic changes make it difficult for the fix tool to update automatically.
 </p>
 
+<h3 id="xml">The xml package</h3>
+
+<p>
+In Go 1, the <a href="/pkg/encoding/xml/"><code>xml</code></a> package
+has been brought closer in design to the other marshaling packages such
+as <a href="/pkg/encoding/gob/"><code>encoding/gob</code></a>.
+</p>
+
+<p>
+The old <code>Parser</code> type is renamed
+<a href="/pkg/encoding/xml/#Decoder"><code>Decoder</code></a> and has a new
+<a href="/pkg/encoding/xml/#Decoder.Decode"><code>Decode</code></a> method. An
+<a href="/pkg/encoding/xml/#Encoder"><code>Encoder</code></a> type was also
+introduced.
+</p>
+
+<p>
+The functions <a href="/pkg/encoding/xml/#Marshal"><code>Marshal</code></a>
+and <a href="/pkg/encoding/xml/#Unmarshal"><code>Unmarshal</code></a>
+work with <code>[]byte</code> values now. To work with streams,
+use the new <a href="/pkg/encoding/xml/#Encoder"><code>Encoder</code></a>
+and <a href="/pkg/encoding/xml/#Decoder"><code>Decoder</code></a> types.
+</p>
+
+<p>
+When marshaling or unmarshaling values, the format of supported flags in
+field tags has changed to be closer to the
+<a href="/pkg/encoding/json"><code>json</code></a> package
+(<code>`xml:"name,flag"`</code>). The matching done between field tags, field
+names, and the XML attribute and element names is now case-sensitive.
+The <code>XMLName</code> field tag, if present, must also match the name
+of the XML element being marshaled.
+</p>
+
+<p>
+<em>Updating</em>:
+Running <code>go fix</code> will update most uses of the package except for some calls to
+<code>Unmarshal</code>. Special care must be taken with field tags,
+since the fix tool will not update them and if not fixed by hand they will
+misbehave silently in some cases. For example, the old
+<code>"attr"</code> is now written <code>",attr"</code> while plain
+<code>"attr"</code> remains valid but with a different meaning.
+</p>
+
 <h2 id="go_command">The go command</h2>
 
 <h2 id="releases">Packaged releases</h2>

doc/go1.tmpl

@@ -759,38 +759,23 @@ few programs beyond the need to run <code>go fix</code>.
 This category includes packages that are new in Go 1.
 </p>
 
-<h3 id="bufio">The bufio package</h3>
+<h3 id="crypto_aes_des">The crypto/aes and crypto/des packages</h3>
 
 <p>
-In Go 1, <a href="/pkg/bufio/#NewReaderSize"><code>bufio.NewReaderSize</code></a>
+In Go 1, the <code>Reset</code> method has been removed. Go does not guarantee
-and
+that memory is not copied and therefore this method was misleading.
-<a href="/pkg/bufio/#NewWriterSize"><code>bufio.NewWriterSize</code></a>
+</p>
-functions no longer return an error for invalid sizes.
+
-If the argument size is too small or invalid, it is adjusted.
+<p>
+The cipher-specific types <code>*aes.Cipher</code>, <code>*des.Cipher</code>,
+and <code>*des.TripleDESCipher</code> have been removed in favor of
+<code>cipher.Block</code>.
 </p>
 
 <p>
 <em>Updating</em>:
-What little code is affected will be caught by the compiler and must be updated by hand.
+Remove the calls to Reset. Replace uses of the specific cipher types with
-</p>
+cipher.Block.
-
-<h3 id="bufio">The compress/flate, compress/gzip and compress/zlib packages</h3>
-
-<p>
-In Go 1, the <code>NewWriterXxx</code> functions in
-<a href="/pkg/compress/flate"><code>compress/flate</code></a>,
-<a href="/pkg/compress/gzip"><code>compress/gzip</code></a> and
-<a href="/pkg/compress/zlib"><code>compress/zlib</code></a>
-all return <code>(*Writer, error)</code> if they take a compression level,
-and <code>*Writer</code> otherwise. Package <code>gzip</code>'s
-<code>Compressor</code> and <code>Decompressor</code> types have been renamed
-to <code>Writer</code> and <code>Reader</code>. Package <code>flate</code>'s
-<code>WrongValueError</code> type has been removed.
-</p>
-
-<p>
-<em>Updating</em>:
-What little code is affected will be caught by the compiler and must be updated by hand.
 </p>
 
 <h3 id="crypto_elliptic">The crypto/elliptic package</h3>
@@ -843,64 +828,6 @@ to be implemented in the future.
 No changes will be needed.
 </p>
 
-<h3 id="encoding_binary">The encoding/binary package</h3>
-
-<p>
-In Go 1, the <code>binary.TotalSize</code> function has been replaced by
-<a href="/pkg/encoding/binary/#Size"><code>Size</code></a>,
-which takes an <code>interface{}</code> argument rather than
-a <code>reflect.Value</code>.
-</p>
-
-<p>
-<em>Updating</em>:
-What little code is affected will be caught by the compiler and must be updated by hand.
-</p>
-
-<h3 id="encoding_xml">The encoding/xml package</h3>
-
-<p>
-In Go 1, the <a href="/pkg/encoding/xml/"><code>xml</code></a> package
-has been brought closer in design to the other marshaling packages such
-as <a href="/pkg/encoding/gob/"><code>encoding/gob</code></a>.
-</p>
-
-<p>
-The old <code>Parser</code> type is renamed
-<a href="/pkg/encoding/xml/#Decoder"><code>Decoder</code></a> and has a new
-<a href="/pkg/encoding/xml/#Decoder.Decode"><code>Decode</code></a> method. An
-<a href="/pkg/encoding/xml/#Encoder"><code>Encoder</code></a> type was also
-introduced.
-</p>
-
-<p>
-The functions <a href="/pkg/encoding/xml/#Marshal"><code>Marshal</code></a>
-and <a href="/pkg/encoding/xml/#Unmarshal"><code>Unmarshal</code></a>
-work with <code>[]byte</code> values now. To work with streams,
-use the new <a href="/pkg/encoding/xml/#Encoder"><code>Encoder</code></a>
-and <a href="/pkg/encoding/xml/#Decoder"><code>Decoder</code></a> types.
-</p>
-
-<p>
-When marshaling or unmarshaling values, the format of supported flags in
-field tags has changed to be closer to the
-<a href="/pkg/encoding/json"><code>json</code></a> package
-(<code>`xml:"name,flag"`</code>). The matching done between field tags, field
-names, and the XML attribute and element names is now case-sensitive.
-The <code>XMLName</code> field tag, if present, must also match the name
-of the XML element being marshaled.
-</p>
-
-<p>
-<em>Updating</em>:
-Running <code>go fix</code> will update most uses of the package except for some calls to
-<code>Unmarshal</code>. Special care must be taken with field tags,
-since the fix tool will not update them and if not fixed by hand they will
-misbehave silently in some cases. For example, the old
-<code>"attr"</code> is now written <code>",attr"</code> while plain
-<code>"attr"</code> remains valid but with a different meaning.
-</p>
-
 <h3 id="expvar">The expvar package</h3>
 
 <p>
@@ -949,15 +876,6 @@ The <code>Duration</code> flag is new and affects no existing code.
 Several packages under <code>go</code> have slightly revised APIs.
 </p>
 
-<p>
-A concrete <code>Mode</code> type was introduced for configuration mode flags
-in the packages
-<a href="/pkg/go/scanner/"><code>go/scanner</code></a>,
-<a href="/pkg/go/parser/"><code>go/parser</code></a>,
-<a href="/pkg/go/printer/"><code>go/printer</code></a>, and
-<a href="/pkg/go/doc/"><code>go/doc</code></a>.
-</p>
-
 <p>
 The modes <code>AllowIllegalChars</code> and <code>InsertSemis</code> have been removed
 from the <a href="/pkg/go/scanner/"><code>go/scanner</code></a> package. They were mostly
@@ -966,16 +884,6 @@ useful for scanning text other then Go source files. Instead, the
 for that purpose.
 </p>
 
-<p>
-The <a href="/pkg/go/scanner/#ErrorHandler"><code>ErrorHandler</code></a> provided
-to the scanner's <a href="/pkg/go/scanner/#Scanner.Init"><code>Init</code></a> method is
-now simply a function rather than an interface. The <code>ErrorVector</code> type has
-been removed in favor of the (existing) <a href="/pkg/go/scanner/#ErrorList"><code>ErrorList</code></a>
-type, and the <code>ErrorVector</code> methods have been migrated. Instead of embedding
-an <code>ErrorVector</code> in a client of the scanner, now a client should maintain
-an <code>ErrorList</code>.
-</p>
-
 <p>
 The set of parse functions provided by the <a href="/pkg/go/parser/"><code>go/parser</code></a>
 package has been reduced to the primary parse function
@@ -984,17 +892,6 @@ convenience functions <a href="/pkg/go/parser/#ParseDir"><code>ParseDir</code></
 and <a href="/pkg/go/parser/#ParseExpr"><code>ParseExpr</code></a>.
 </p>
 
-<p>
-The <a href="/pkg/go/printer/"><code>go/printer</code></a> package supports an additional
-configuration mode <a href="/pkg/go/printer/#Mode"><code>SourcePos</code></a>;
-if set, the printer will emit <code>//line</code> comments such that the generated
-output contains the original source code position information. The new type
-<a href="/pkg/go/printer/#CommentedNode"><code>CommentedNode</code></a> can be
-used to provide comments associated with an arbitrary
-<a href="/pkg/go/ast/#Node"><code>ast.Node</code></a> (until now only
-<a href="/pkg/go/ast/#File"><code>ast.File</code></a> carried comment information).
-</p>
-
 <p>
 The type names of the <a href="/pkg/go/doc/"><code>go/doc</code></a> package have been
 streamlined by removing the <code>Doc</code> suffix: <code>PackageDoc</code>
@@ -1092,16 +989,10 @@ The affected items are:
 </ul>
 
 <p>
-The <code>Request.RawURL</code> field has been removed; it was a
+Also, the <code>Request.RawURL</code> field has been removed; it was a
 historical artifact.
 </p>
 
-<p>
-The <code>Handle</code> and <code>HandleFunc</code>
-functions, and the similarly-named methods of <code>ServeMux</code>,
-now panic if an attempt is made to register the same pattern twice.
-</p>
-
 <p>
 <em>Updating</em>:
 Running <code>go fix</code> will update the few programs that are affected except for
@@ -1138,7 +1029,9 @@ packages.
 The old <code>image.ColorImage</code> type is still in the <code>image</code>
 package but has been renamed
 <a href="/pkg/image/#Uniform"><code>image.Uniform</code></a>,
-while <code>image.Tiled</code> has been removed.
+while <code>image.Tiled</code>
+has been renamed
+<a href="/pkg/image/#Repeated"><code>image.Repeated</code></a>.
 </p>
 
 <p>
@@ -1199,6 +1092,7 @@ This table lists the renamings.
 <td colspan="2"><hr></td>
 </tr>
 <tr><td>image.ColorImage</td> <td>image.Uniform</td></tr>
+<tr><td>image.Tiled</td> <td>image.Repeated</td></tr>
 </table>
 
 <p>
@@ -1223,18 +1117,6 @@ and
 Running <code>go fix</code> will update almost all code affected by the change.
 </p>
 
-<h3 id="log_syslog">The log/syslog package</h3>
-
-<p>
-In Go 1, the <a href="/pkg/log/syslog/#NewLogger"><code>syslog.NewLogger</code></a>
-function returns an error as well as a <code>log.Logger</code>.
-</p>
-
-<p>
-<em>Updating</em>:
-What little code is affected will be caught by the compiler and must be updated by hand.
-</p>
-
 <h3 id="mime">The mime package</h3>
 
 <p>
@@ -1281,27 +1163,7 @@ Code that uses the old methods will fail to compile and must be updated by hand.
 The semantic change makes it difficult for the fix tool to update automatically.
 </p>
 
-<h3 id="os">The os package</h3>
+<h3 id="os_fileinfo">The os.FileInfo type</h3>
-
-<p>The <code>Time</code> function has been removed; callers should use
-the <a href="/pkg/time/#Time"><code>Time</code></a> type from the
-<code>time</code> package.</p>
-
-<p>The <code>Exec</code> function has been removed; callers should use
-<code>Exec</code> from the <code>syscall</code> package, where available.</p>
-
-<p>The <code>ShellExpand</code> function has been renamed to <a
-href="/pkg/os/#ExpandEnv"><code>ExpandEnv</code></a>.</p>
-
-<p>The <a href="/pkg/os/#NewFile"><code>NewFile</code></a> function
-now takes a <code>uintptr</code> fd, instead of an <code>int</code>.
-The <a href="/pkg/os/#File.Fd"><code>Fd</code></a> method on files now
-also returns a <code>uintptr</code>.</p>
-
-<p><em>Updating</em>: Code will fail to compile and must be updated
-by hand.  </p>
-
-<h4 id="os_fileinfo">The os.FileInfo type</h4>
 
 <p>
 Go 1 redefines the <a href="/pkg/os/#FileInfo"><code>os.FileInfo</code></a> type,
@@ -1529,17 +1391,6 @@ Existing code is unaffected, although benchmarks that use <code>println</code>
 or <code>panic</code> should be updated to use the new methods.
 </p>
 
-<h3 id="testing_script">The testing/script package</h3>
-
-<p>
-The testing/script package has been deleted. It was a dreg.
-</p>
-
-<p>
-<em>Updating</em>:
-No code is likely to be affected.
-</p>
-
 <h3 id="url">The url package</h3>
 
 <p>
@@ -1608,6 +1459,50 @@ Code that uses the old fields will fail to compile and must be updated by hand.
 The semantic changes make it difficult for the fix tool to update automatically.
 </p>
 
+<h3 id="xml">The xml package</h3>
+
+<p>
+In Go 1, the <a href="/pkg/encoding/xml/"><code>xml</code></a> package
+has been brought closer in design to the other marshaling packages such
+as <a href="/pkg/encoding/gob/"><code>encoding/gob</code></a>.
+</p>
+
+<p>
+The old <code>Parser</code> type is renamed
+<a href="/pkg/encoding/xml/#Decoder"><code>Decoder</code></a> and has a new
+<a href="/pkg/encoding/xml/#Decoder.Decode"><code>Decode</code></a> method. An
+<a href="/pkg/encoding/xml/#Encoder"><code>Encoder</code></a> type was also
+introduced.
+</p>
+
+<p>
+The functions <a href="/pkg/encoding/xml/#Marshal"><code>Marshal</code></a>
+and <a href="/pkg/encoding/xml/#Unmarshal"><code>Unmarshal</code></a>
+work with <code>[]byte</code> values now. To work with streams,
+use the new <a href="/pkg/encoding/xml/#Encoder"><code>Encoder</code></a>
+and <a href="/pkg/encoding/xml/#Decoder"><code>Decoder</code></a> types.
+</p>
+
+<p>
+When marshaling or unmarshaling values, the format of supported flags in
+field tags has changed to be closer to the
+<a href="/pkg/encoding/json"><code>json</code></a> package
+(<code>`xml:"name,flag"`</code>). The matching done between field tags, field
+names, and the XML attribute and element names is now case-sensitive.
+The <code>XMLName</code> field tag, if present, must also match the name
+of the XML element being marshaled.
+</p>
+
+<p>
+<em>Updating</em>:
+Running <code>go fix</code> will update most uses of the package except for some calls to
+<code>Unmarshal</code>. Special care must be taken with field tags,
+since the fix tool will not update them and if not fixed by hand they will
+misbehave silently in some cases. For example, the old
+<code>"attr"</code> is now written <code>",attr"</code> while plain
+<code>"attr"</code> remains valid but with a different meaning.
+</p>
+
 <h2 id="go_command">The go command</h2>
 
 <h2 id="releases">Packaged releases</h2>

src/pkg/crypto/aes/cipher.go

@@ -4,13 +4,16 @@
 
 package aes
 
-import "strconv"
+import (
+	"crypto/cipher"
+	"strconv"
+)
 
 // The AES block size in bytes.
 const BlockSize = 16
 
-// A Cipher is an instance of AES encryption using a particular key.
+// A cipher is an instance of AES encryption using a particular key.
-type Cipher struct {
+type aesCipher struct {
 	enc []uint32
 	dec []uint32
 }
@@ -21,11 +24,11 @@ func (k KeySizeError) Error() string {
 	return "crypto/aes: invalid key size " + strconv.Itoa(int(k))
 }
 
-// NewCipher creates and returns a new Cipher.
+// NewCipher creates and returns a new cipher.Block.
 // The key argument should be the AES key,
 // either 16, 24, or 32 bytes to select
 // AES-128, AES-192, or AES-256.
-func NewCipher(key []byte) (*Cipher, error) {
+func NewCipher(key []byte) (cipher.Block, error) {
 	k := len(key)
 	switch k {
 	default:
@@ -35,34 +38,13 @@ func NewCipher(key []byte) (*Cipher, error) {
 	}
 
 	n := k + 28
-	c := &Cipher{make([]uint32, n), make([]uint32, n)}
+	c := &aesCipher{make([]uint32, n), make([]uint32, n)}
 	expandKey(key, c.enc, c.dec)
 	return c, nil
 }
 
-// BlockSize returns the AES block size, 16 bytes.
+func (c *aesCipher) BlockSize() int { return BlockSize }
-// It is necessary to satisfy the Block interface in the
-// package "crypto/cipher".
-func (c *Cipher) BlockSize() int { return BlockSize }
 
-// Encrypt encrypts the 16-byte buffer src using the key k
+func (c *aesCipher) Encrypt(dst, src []byte) { encryptBlock(c.enc, dst, src) }
-// and stores the result in dst.
-// Note that for amounts of data larger than a block,
-// it is not safe to just call Encrypt on successive blocks;
-// instead, use an encryption mode like CBC (see crypto/cipher/cbc.go).
-func (c *Cipher) Encrypt(dst, src []byte) { encryptBlock(c.enc, dst, src) }
 
-// Decrypt decrypts the 16-byte buffer src using the key k
+func (c *aesCipher) Decrypt(dst, src []byte) { decryptBlock(c.dec, dst, src) }
-// and stores the result in dst.
-func (c *Cipher) Decrypt(dst, src []byte) { decryptBlock(c.dec, dst, src) }
-
-// Reset zeros the key data, so that it will no longer
-// appear in the process's memory.
-func (c *Cipher) Reset() {
-	for i := 0; i < len(c.enc); i++ {
-		c.enc[i] = 0
-	}
-	for i := 0; i < len(c.dec); i++ {
-		c.dec[i] = 0
-	}
-}

src/pkg/crypto/cipher/cbc_aes_test.go

@@ -8,11 +8,12 @@
 // Special Publication 800-38A, ``Recommendation for Block Cipher
 // Modes of Operation,'' 2001 Edition, pp. 24-29.
 
-package cipher
+package cipher_test
 
 import (
 	"bytes"
 	"crypto/aes"
+	"crypto/cipher"
 	"testing"
 )
 
@@ -72,14 +73,14 @@ func TestCBC_AES(t *testing.T) {
 			continue
 		}
 
-		encrypter := NewCBCEncrypter(c, tt.iv)
+		encrypter := cipher.NewCBCEncrypter(c, tt.iv)
 		d := make([]byte, len(tt.in))
 		encrypter.CryptBlocks(d, tt.in)
 		if !bytes.Equal(tt.out, d) {
 			t.Errorf("%s: CBCEncrypter\nhave %x\nwant %x", test, d, tt.out)
 		}
 
-		decrypter := NewCBCDecrypter(c, tt.iv)
+		decrypter := cipher.NewCBCDecrypter(c, tt.iv)
 		p := make([]byte, len(d))
 		decrypter.CryptBlocks(p, d)
 		if !bytes.Equal(tt.in, p) {

src/pkg/crypto/cipher/cfb_test.go

@@ -2,11 +2,12 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package cipher
+package cipher_test
 
 import (
 	"bytes"
 	"crypto/aes"
+	"crypto/cipher"
 	"crypto/rand"
 	"testing"
 )
@@ -21,11 +22,11 @@ func TestCFB(t *testing.T) {
 	plaintext := []byte("this is the plaintext")
 	iv := make([]byte, block.BlockSize())
 	rand.Reader.Read(iv)
-	cfb := NewCFBEncrypter(block, iv)
+	cfb := cipher.NewCFBEncrypter(block, iv)
 	ciphertext := make([]byte, len(plaintext))
 	cfb.XORKeyStream(ciphertext, plaintext)
 
-	cfbdec := NewCFBDecrypter(block, iv)
+	cfbdec := cipher.NewCFBDecrypter(block, iv)
 	plaintextCopy := make([]byte, len(plaintext))
 	cfbdec.XORKeyStream(plaintextCopy, ciphertext)
 

src/pkg/crypto/cipher/common_test.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package cipher
+package cipher_test
 
 // Common values for tests.
 

src/pkg/crypto/cipher/ctr_aes_test.go

@@ -8,11 +8,12 @@
 // Special Publication 800-38A, ``Recommendation for Block Cipher
 // Modes of Operation,'' 2001 Edition, pp. 55-58.
 
-package cipher
+package cipher_test
 
 import (
 	"bytes"
 	"crypto/aes"
+	"crypto/cipher"
 	"testing"
 )
 
@@ -76,7 +77,7 @@ func TestCTR_AES(t *testing.T) {
 
 		for j := 0; j <= 5; j += 5 {
 			in := tt.in[0 : len(tt.in)-j]
-			ctr := NewCTR(c, tt.iv)
+			ctr := cipher.NewCTR(c, tt.iv)
 			encrypted := make([]byte, len(in))
 			ctr.XORKeyStream(encrypted, in)
 			if out := tt.out[0:len(in)]; !bytes.Equal(out, encrypted) {
@@ -86,7 +87,7 @@ func TestCTR_AES(t *testing.T) {
 
 		for j := 0; j <= 7; j += 7 {
 			in := tt.out[0 : len(tt.out)-j]
-			ctr := NewCTR(c, tt.iv)
+			ctr := cipher.NewCTR(c, tt.iv)
 			plain := make([]byte, len(in))
 			ctr.XORKeyStream(plain, in)
 			if out := tt.in[0:len(in)]; !bytes.Equal(out, plain) {

src/pkg/crypto/cipher/ofb_test.go

@@ -8,11 +8,12 @@
 // Special Publication 800-38A, ``Recommendation for Block Cipher
 // Modes of Operation,'' 2001 Edition, pp. 52-55.
 
-package cipher
+package cipher_test
 
 import (
 	"bytes"
 	"crypto/aes"
+	"crypto/cipher"
 	"testing"
 )
 
@@ -76,7 +77,7 @@ func TestOFB(t *testing.T) {
 
 		for j := 0; j <= 5; j += 5 {
 			plaintext := tt.in[0 : len(tt.in)-j]
-			ofb := NewOFB(c, tt.iv)
+			ofb := cipher.NewOFB(c, tt.iv)
 			ciphertext := make([]byte, len(plaintext))
 			ofb.XORKeyStream(ciphertext, plaintext)
 			if !bytes.Equal(ciphertext, tt.out[:len(plaintext)]) {
@@ -86,7 +87,7 @@ func TestOFB(t *testing.T) {
 
 		for j := 0; j <= 5; j += 5 {
 			ciphertext := tt.out[0 : len(tt.in)-j]
-			ofb := NewOFB(c, tt.iv)
+			ofb := cipher.NewOFB(c, tt.iv)
 			plaintext := make([]byte, len(ciphertext))
 			ofb.XORKeyStream(plaintext, ciphertext)
 			if !bytes.Equal(plaintext, tt.in[:len(ciphertext)]) {

src/pkg/crypto/des/block.go

@@ -79,7 +79,7 @@ func ksRotate(in uint32) (out []uint32) {
 }
 
 // creates 16 56-bit subkeys from the original key
-func (c *Cipher) generateSubkeys(keyBytes []byte) {
+func (c *desCipher) generateSubkeys(keyBytes []byte) {
 	// apply PC1 permutation to key
 	key := binary.BigEndian.Uint64(keyBytes)
 	permutedKey := permuteBlock(key, permutedChoice1[:])

src/pkg/crypto/des/cipher.go

@@ -4,7 +4,10 @@
 
 package des
 
-import "strconv"
+import (
+	"crypto/cipher"
+	"strconv"
+)
 
 // The DES block size in bytes.
 const BlockSize = 8
@@ -15,86 +18,56 @@ func (k KeySizeError) Error() string {
 	return "crypto/des: invalid key size " + strconv.Itoa(int(k))
 }
 
-// Cipher is an instance of DES encryption.
+// desCipher is an instance of DES encryption.
-type Cipher struct {
+type desCipher struct {
 	subkeys [16]uint64
 }
 
-// NewCipher creates and returns a new Cipher.
+// NewCipher creates and returns a new cipher.Block.
-func NewCipher(key []byte) (*Cipher, error) {
+func NewCipher(key []byte) (cipher.Block, error) {
 	if len(key) != 8 {
 		return nil, KeySizeError(len(key))
 	}
 
-	c := new(Cipher)
+	c := new(desCipher)
 	c.generateSubkeys(key)
 	return c, nil
 }
 
-// BlockSize returns the DES block size, 8 bytes.
+func (c *desCipher) BlockSize() int { return BlockSize }
-func (c *Cipher) BlockSize() int { return BlockSize }
 
-// Encrypt encrypts the 8-byte buffer src and stores the result in dst.
+func (c *desCipher) Encrypt(dst, src []byte) { encryptBlock(c.subkeys[:], dst, src) }
-// Note that for amounts of data larger than a block,
-// it is not safe to just call Encrypt on successive blocks;
-// instead, use an encryption mode like CBC (see crypto/cipher/cbc.go).
-func (c *Cipher) Encrypt(dst, src []byte) { encryptBlock(c.subkeys[:], dst, src) }
 
-// Decrypt decrypts the 8-byte buffer src and stores the result in dst.
+func (c *desCipher) Decrypt(dst, src []byte) { decryptBlock(c.subkeys[:], dst, src) }
-func (c *Cipher) Decrypt(dst, src []byte) { decryptBlock(c.subkeys[:], dst, src) }
 
-// Reset zeros the key data, so that it will no longer
+// A tripleDESCipher is an instance of TripleDES encryption.
-// appear in the process's memory.
+type tripleDESCipher struct {
-func (c *Cipher) Reset() {
+	cipher1, cipher2, cipher3 desCipher
-	for i := 0; i < len(c.subkeys); i++ {
-		c.subkeys[i] = 0
-	}
 }
 
-// A TripleDESCipher is an instance of TripleDES encryption.
+// NewTripleDESCipher creates and returns a new cipher.Block.
-type TripleDESCipher struct {
+func NewTripleDESCipher(key []byte) (cipher.Block, error) {
-	cipher1, cipher2, cipher3 Cipher
-}
-
-// NewCipher creates and returns a new Cipher.
-func NewTripleDESCipher(key []byte) (*TripleDESCipher, error) {
 	if len(key) != 24 {
 		return nil, KeySizeError(len(key))
 	}
 
-	c := new(TripleDESCipher)
+	c := new(tripleDESCipher)
 	c.cipher1.generateSubkeys(key[:8])
 	c.cipher2.generateSubkeys(key[8:16])
 	c.cipher3.generateSubkeys(key[16:])
 	return c, nil
 }
 
-// BlockSize returns the TripleDES block size, 8 bytes.
+func (c *tripleDESCipher) BlockSize() int { return BlockSize }
-// It is necessary to satisfy the Block interface in the
-// package "crypto/cipher".
-func (c *TripleDESCipher) BlockSize() int { return BlockSize }
 
-// Encrypts the 8-byte buffer src and stores the result in dst.
+func (c *tripleDESCipher) Encrypt(dst, src []byte) {
-// Note that for amounts of data larger than a block,
-// it is not safe to just call Encrypt on successive blocks;
-// instead, use an encryption mode like CBC (see crypto/cipher/cbc.go).
-func (c *TripleDESCipher) Encrypt(dst, src []byte) {
 	c.cipher1.Encrypt(dst, src)
 	c.cipher2.Decrypt(dst, dst)
 	c.cipher3.Encrypt(dst, dst)
 }
 
-// Decrypts the 8-byte buffer src and stores the result in dst.
+func (c *tripleDESCipher) Decrypt(dst, src []byte) {
-func (c *TripleDESCipher) Decrypt(dst, src []byte) {
 	c.cipher3.Decrypt(dst, src)
 	c.cipher2.Encrypt(dst, dst)
 	c.cipher1.Decrypt(dst, dst)
 }
-
-// Reset zeros the key data, so that it will no longer
-// appear in the process's memory.
-func (c *TripleDESCipher) Reset() {
-	c.cipher1.Reset()
-	c.cipher2.Reset()
-	c.cipher3.Reset()
-}

src/pkg/crypto/des/des_test.go

@@ -1260,11 +1260,19 @@ var tableA4Tests = []CryptTest{
 		[]byte{0x63, 0xfa, 0xc0, 0xd0, 0x34, 0xd9, 0xf7, 0x93}},
 }
 
+func newCipher(key []byte) *desCipher {
+	c, err := NewCipher(key)
+	if err != nil {
+		panic("NewCipher failed: " + err.Error())
+	}
+	return c.(*desCipher)
+}
+
 // Use the known weak keys to test DES implementation
 func TestWeakKeys(t *testing.T) {
 	for i, tt := range weakKeyTests {
 		var encrypt = func(in []byte) (out []byte) {
-			c, _ := NewCipher(tt.key)
+			c := newCipher(tt.key)
 			out = make([]byte, len(in))
 			encryptBlock(c.subkeys[:], out, in)
 			return
@@ -1285,7 +1293,7 @@ func TestWeakKeys(t *testing.T) {
 func TestSemiWeakKeyPairs(t *testing.T) {
 	for i, tt := range semiWeakKeyTests {
 		var encrypt = func(key, in []byte) (out []byte) {
-			c, _ := NewCipher(key)
+			c := newCipher(key)
 			out = make([]byte, len(in))
 			encryptBlock(c.subkeys[:], out, in)
 			return
@@ -1305,7 +1313,7 @@ func TestSemiWeakKeyPairs(t *testing.T) {
 
 func TestDESEncryptBlock(t *testing.T) {
 	for i, tt := range encryptDESTests {
-		c, _ := NewCipher(tt.key)
+		c := newCipher(tt.key)
 		out := make([]byte, len(tt.in))
 		encryptBlock(c.subkeys[:], out, tt.in)
 
@@ -1317,7 +1325,7 @@ func TestDESEncryptBlock(t *testing.T) {
 
 func TestDESDecryptBlock(t *testing.T) {
 	for i, tt := range encryptDESTests {
-		c, _ := NewCipher(tt.key)
+		c := newCipher(tt.key)
 		plain := make([]byte, len(tt.in))
 		decryptBlock(c.subkeys[:], plain, tt.out)
 

src/pkg/crypto/dsa/dsa.go

@@ -29,17 +29,11 @@ type PrivateKey struct {
 	X *big.Int
 }
 
-type invalidPublicKeyError int
-
-func (invalidPublicKeyError) Error() string {
-	return "crypto/dsa: invalid public key"
-}
-
 // ErrInvalidPublicKey results when a public key is not usable by this code.
 // FIPS is quite strict about the format of DSA keys, but other code may be
 // less so. Thus, when using keys which may have been generated by other code,
 // this error must be handled.
-var ErrInvalidPublicKey error = invalidPublicKeyError(0)
+var ErrInvalidPublicKey = errors.New("crypto/dsa: invalid public key")
 
 // ParameterSizes is a enumeration of the acceptable bit lengths of the primes
 // in a set of DSA parameters. See FIPS 186-3, section 4.2.

src/pkg/crypto/rand/rand_unix.go

@@ -12,6 +12,7 @@ package rand
 import (
 	"bufio"
 	"crypto/aes"
+	"crypto/cipher"
 	"io"
 	"os"
 	"sync"
@@ -66,7 +67,7 @@ func newReader(entropy io.Reader) io.Reader {
 type reader struct {
 	mu                   sync.Mutex
 	budget               int // number of bytes that can be generated
-	cipher               *aes.Cipher
+	cipher               cipher.Block
 	entropy              io.Reader
 	time, seed, dst, key [aes.BlockSize]byte
 }

src/pkg/crypto/rsa/pkcs1v15.go

@@ -21,7 +21,7 @@ import (
 func EncryptPKCS1v15(rand io.Reader, pub *PublicKey, msg []byte) (out []byte, err error) {
 	k := (pub.N.BitLen() + 7) / 8
 	if len(msg) > k-11 {
-		err = MessageTooLongError{}
+		err = ErrMessageTooLong
 		return
 	}
 
@@ -47,7 +47,7 @@ func EncryptPKCS1v15(rand io.Reader, pub *PublicKey, msg []byte) (out []byte, er
 func DecryptPKCS1v15(rand io.Reader, priv *PrivateKey, ciphertext []byte) (out []byte, err error) {
 	valid, out, err := decryptPKCS1v15(rand, priv, ciphertext)
 	if err == nil && valid == 0 {
-		err = DecryptionError{}
+		err = ErrDecryption
 	}
 
 	return
@@ -69,7 +69,7 @@ func DecryptPKCS1v15(rand io.Reader, priv *PrivateKey, ciphertext []byte) (out [
 func DecryptPKCS1v15SessionKey(rand io.Reader, priv *PrivateKey, ciphertext []byte, key []byte) (err error) {
 	k := (priv.N.BitLen() + 7) / 8
 	if k-(len(key)+3+8) < 0 {
-		err = DecryptionError{}
+		err = ErrDecryption
 		return
 	}
 
@@ -86,7 +86,7 @@ func DecryptPKCS1v15SessionKey(rand io.Reader, priv *PrivateKey, ciphertext []by
 func decryptPKCS1v15(rand io.Reader, priv *PrivateKey, ciphertext []byte) (valid int, msg []byte, err error) {
 	k := (priv.N.BitLen() + 7) / 8
 	if k < 11 {
-		err = DecryptionError{}
+		err = ErrDecryption
 		return
 	}
 
@@ -170,7 +170,7 @@ func SignPKCS1v15(rand io.Reader, priv *PrivateKey, hash crypto.Hash, hashed []b
 	tLen := len(prefix) + hashLen
 	k := (priv.N.BitLen() + 7) / 8
 	if k < tLen+11 {
-		return nil, MessageTooLongError{}
+		return nil, ErrMessageTooLong
 	}
 
 	// EM = 0x00 || 0x01 || PS || 0x00 || T
@@ -203,7 +203,7 @@ func VerifyPKCS1v15(pub *PublicKey, hash crypto.Hash, hashed []byte, sig []byte)
 	tLen := len(prefix) + hashLen
 	k := (pub.N.BitLen() + 7) / 8
 	if k < tLen+11 {
-		err = VerificationError{}
+		err = ErrVerification
 		return
 	}
 
@@ -223,7 +223,7 @@ func VerifyPKCS1v15(pub *PublicKey, hash crypto.Hash, hashed []byte, sig []byte)
 	}
 
 	if ok != 1 {
-		return VerificationError{}
+		return ErrVerification
 	}
 
 	return nil

src/pkg/crypto/rsa/rsa.go

@@ -206,13 +206,9 @@ func mgf1XOR(out []byte, hash hash.Hash, seed []byte) {
 	}
 }
 
-// MessageTooLongError is returned when attempting to encrypt a message which
+// ErrMessageTooLong is returned when attempting to encrypt a message which is
-// is too large for the size of the public key.
+// too large for the size of the public key.
-type MessageTooLongError struct{}
+var ErrMessageTooLong = errors.New("crypto/rsa: message too long for RSA public key size")
-
-func (MessageTooLongError) Error() string {
-	return "message too long for RSA public key size"
-}
 
 func encrypt(c *big.Int, pub *PublicKey, m *big.Int) *big.Int {
 	e := big.NewInt(int64(pub.E))
@@ -227,7 +223,7 @@ func EncryptOAEP(hash hash.Hash, random io.Reader, pub *PublicKey, msg []byte, l
 	hash.Reset()
 	k := (pub.N.BitLen() + 7) / 8
 	if len(msg) > k-2*hash.Size()-2 {
-		err = MessageTooLongError{}
+		err = ErrMessageTooLong
 		return
 	}
 
@@ -266,17 +262,13 @@ func EncryptOAEP(hash hash.Hash, random io.Reader, pub *PublicKey, msg []byte, l
 	return
 }
 
-// A DecryptionError represents a failure to decrypt a message.
+// ErrDecryption represents a failure to decrypt a message.
 // It is deliberately vague to avoid adaptive attacks.
-type DecryptionError struct{}
+var ErrDecryption = errors.New("crypto/rsa: decryption error")
 
-func (DecryptionError) Error() string { return "RSA decryption error" }
+// ErrVerification represents a failure to verify a signature.
-
-// A VerificationError represents a failure to verify a signature.
 // It is deliberately vague to avoid adaptive attacks.
-type VerificationError struct{}
+var ErrVerification = errors.New("crypto/rsa: verification error")
-
-func (VerificationError) Error() string { return "RSA verification error" }
 
 // modInverse returns ia, the inverse of a in the multiplicative group of prime
 // order n. It requires that a be a member of the group (i.e. less than n).
@@ -338,7 +330,7 @@ func (priv *PrivateKey) Precompute() {
 func decrypt(random io.Reader, priv *PrivateKey, c *big.Int) (m *big.Int, err error) {
 	// TODO(agl): can we get away with reusing blinds?
 	if c.Cmp(priv.N) > 0 {
-		err = DecryptionError{}
+		err = ErrDecryption
 		return
 	}
 
@@ -417,7 +409,7 @@ func DecryptOAEP(hash hash.Hash, random io.Reader, priv *PrivateKey, ciphertext
 	k := (priv.N.BitLen() + 7) / 8
 	if len(ciphertext) > k ||
 		k < hash.Size()*2+2 {
-		err = DecryptionError{}
+		err = ErrDecryption
 		return
 	}
 
@@ -473,7 +465,7 @@ func DecryptOAEP(hash hash.Hash, random io.Reader, priv *PrivateKey, ciphertext
 	}
 
 	if firstByteIsZero&lHash2Good&^invalid&^lookingForIndex != 1 {
-		err = DecryptionError{}
+		err = ErrDecryption
 		return
 	}
 

src/pkg/crypto/tls/conn.go

@@ -87,9 +87,9 @@ func (c *Conn) RemoteAddr() net.Addr {
 	return c.conn.RemoteAddr()
 }
 
-// SetDeadline sets the read deadline associated with the connection.
+// SetDeadline sets the read and write deadlines associated with the connection.
-// There is no write deadline.
+// A zero value for t means Read and Write will not time out.
-// A zero value for t means Read will not time out.
+// After a Write has timed out, the TLS state is corrupt and all future writes will return the same error.
 func (c *Conn) SetDeadline(t time.Time) error {
 	return c.conn.SetDeadline(t)
 }
@@ -100,10 +100,11 @@ func (c *Conn) SetReadDeadline(t time.Time) error {
 	return c.conn.SetReadDeadline(t)
 }
 
-// SetWriteDeadline exists to satisfy the net.Conn interface
+// SetWriteDeadline sets the write deadline on the underlying conneciton.
-// but is not implemented by TLS.  It always returns an error.
+// A zero value for t means Write will not time out.
+// After a Write has timed out, the TLS state is corrupt and all future writes will return the same error.
 func (c *Conn) SetWriteDeadline(t time.Time) error {
-	return errors.New("TLS does not support SetWriteDeadline")
+	return c.conn.SetWriteDeadline(t)
 }
 
 // A halfConn represents one direction of the record layer
@@ -726,9 +727,13 @@ func (c *Conn) readHandshake() (interface{}, error) {
 }
 
 // Write writes data to the connection.
-func (c *Conn) Write(b []byte) (n int, err error) {
+func (c *Conn) Write(b []byte) (int, error) {
-	if err = c.Handshake(); err != nil {
+	if c.err != nil {
-		return
+		return 0, c.err
+	}
+
+	if c.err = c.Handshake(); c.err != nil {
+		return 0, c.err
 	}
 
 	c.out.Lock()
@@ -737,10 +742,10 @@ func (c *Conn) Write(b []byte) (n int, err error) {
 	if !c.handshakeComplete {
 		return 0, alertInternalError
 	}
-	if c.err != nil {
+
-		return 0, c.err
+	var n int
-	}
+	n, c.err = c.writeRecord(recordTypeApplicationData, b)
-	return c.writeRecord(recordTypeApplicationData, b)
+	return n, c.err
 }
 
 // Read can be made to time out and return a net.Error with Timeout() == true

src/pkg/crypto/x509/x509.go

@@ -327,13 +327,9 @@ type Certificate struct {
 	PolicyIdentifiers []asn1.ObjectIdentifier
 }
 
-// UnsupportedAlgorithmError results from attempting to perform an operation
+// ErrUnsupportedAlgorithm results from attempting to perform an operation that
-// that involves algorithms that are not currently implemented.
+// involves algorithms that are not currently implemented.
-type UnsupportedAlgorithmError struct{}
+var ErrUnsupportedAlgorithm = errors.New("crypto/x509: cannot verify signature: algorithm unimplemented")
-
-func (UnsupportedAlgorithmError) Error() string {
-	return "cannot verify signature: algorithm unimplemented"
-}
 
 // ConstraintViolationError results when a requested usage is not permitted by
 // a certificate. For example: checking a signature when the public key isn't a
@@ -341,7 +337,7 @@ func (UnsupportedAlgorithmError) Error() string {
 type ConstraintViolationError struct{}
 
 func (ConstraintViolationError) Error() string {
-	return "invalid signature: parent certificate cannot sign this kind of certificate"
+	return "crypto/x509: invalid signature: parent certificate cannot sign this kind of certificate"
 }
 
 func (c *Certificate) Equal(other *Certificate) bool {
@@ -366,7 +362,7 @@ func (c *Certificate) CheckSignatureFrom(parent *Certificate) (err error) {
 	}
 
 	if parent.PublicKeyAlgorithm == UnknownPublicKeyAlgorithm {
-		return UnsupportedAlgorithmError{}
+		return ErrUnsupportedAlgorithm
 	}
 
 	// TODO(agl): don't ignore the path length constraint.
@@ -389,12 +385,12 @@ func (c *Certificate) CheckSignature(algo SignatureAlgorithm, signed, signature
 	case SHA512WithRSA:
 		hashType = crypto.SHA512
 	default:
-		return UnsupportedAlgorithmError{}
+		return ErrUnsupportedAlgorithm
 	}
 
 	h := hashType.New()
 	if h == nil {
-		return UnsupportedAlgorithmError{}
+		return ErrUnsupportedAlgorithm
 	}
 
 	h.Write(signed)
@@ -416,7 +412,7 @@ func (c *Certificate) CheckSignature(algo SignatureAlgorithm, signed, signature
 		}
 		return
 	}
-	return UnsupportedAlgorithmError{}
+	return ErrUnsupportedAlgorithm
 }
 
 // CheckCRLSignature checks that the signature in crl is from c.