wangwei
/
antliscence
forked from youys/ant

<html>

<head>
<meta http-equiv="Content-Language" content="en-us">
<title>Checksum Task</title>
</head>

<body>

<h2><a name="checksum">Checksum</a></h2>
<h3>Description</h3>
<p>
Generates checksum for files.  This task can also be used to
perform checksum verifications.
</p>
<h3>Parameters</h3>
<table border="1" cellpadding="2" cellspacing="0">
  <tr>
    <td valign="top"><b>Attribute</b></td>
    <td valign="top"><b>Description</b></td>
    <td align="center" valign="top"><b>Required</b></td>
  </tr>
  <tr>
    <td valign="top">file</td>
    <td valign="top">The file to generate checksum for.</td>
    <td valign="top" align="center">One of either <var>file</var> or
    at least one nested fileset element.</td>
  </tr>
  <tr>
    <td valign="top">algorithm</td>
    <td valign="top">Specifies the algorithm to be used to
      compute the checksum. Defaults to &quot;MD5&quot;.
      Other popular algorithms like &quot;SHA&quot; may be used
      as well.
    </td>
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top">provider</td>
    <td valign="top">Specifies the provider of the algorithm.</td>
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top">fileext</td>
    <td valign="top">The generated checksum file's name will be the
    original filename with &quot;.&quot; and fileext added to it.
    Defaults to the algorithm name being used.
    </td>
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top">property</td>
    <td valign="top">This attribute can mean two different things, it
    depends on the presence of the verifyproperty attribute.<br/>
    <b>If you don't set the verifyproperty attribute</b>, property
    specifies the name of the property to be set with the generated
    checksum value.<br/>
    <b>If you set the verifyproperty attribute</b>, property specifies
    the checksum you expect to be generated (the checksum itself, not
    a name of a property containing the checksum).<br/>
    This cannot be specified when fileext is being used or when the
    number of files for which checksums is to be generated is greater
    than 1.
    </td>
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top">forceoverwrite</td>
    <td valign="top">Overwrite existing files even if the destination
      files are newer. Defaults to &quot;no&quot;.</td>
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top">verifyproperty</td>
    <td valign="top">Specifies the name of the property to be set
    with &quot;true&quot; or &quot;false&quot; depending upon whether
    the generated checksum matches the existing checksum.  When
    this is set, the generated checksum is not written to a file or
    property, but rather, the content of the file or property is used to
    check against the generated checksum.
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top">readbuffersize</td>
    <td valign="top">The size of the buffer )in bytes) to use when
    reading a file. Defaults to &quot;8192&quot; - you may get a
    better performance on big files if you increase this value.</td>
    <td valign="top" align="center">No</td>
  </tr>
</table>
<h3>Parameters specified as nested elements</h3>

<h4>fileset</h4>
 <p>
 <a href="../CoreTypes/fileset.html">FileSets</a> are used to select files to
 generate checksums for.
 </p>

<h3>Examples</h3>
<p><b>Example 1</b></p>
<pre>&lt;checksum file=&quot;foo.bar&quot;/&gt;</pre>
Generates a MD5 checksum for foo.bar and stores the checksum in the destination file
foo.bar.MD5.  foo.bar.MD5 is overwritten only if foo.bar is newer than itself.

<p><b>Example 2</b></p>
<pre>&lt;checksum file=&quot;foo.bar&quot; forceOverwrite=&quot;yes&quot;/&gt;</pre>
Generates a MD5 checksum for foo.bar and stores the checksum in foo.bar.MD5.
If foo.bar.MD5 already exists, it is overwritten.

<p><b>Example 3</b></p>
<pre>&lt;checksum file=&quot;foo.bar&quot; property=&quot;foobarMD5&quot;/&gt;</pre>
Generates a MD5 checksum for foo.bar and stores it in the Project Property foobarMD5.

<p><b>Example 4</b></p>
<pre>&lt;checksum file=&quot;foo.bar&quot; verifyProperty=&quot;isMD5ok&quot;/&gt;</pre>
Generates a MD5 checksum for foo.bar, compares it against foo.bar.MD5 and sets
isMD5ok to either true or false, depending upon the result.

<p><b>Example 5</b></p>
<pre>&lt;checksum file=&quot;foo.bar&quot; algorithm=&quot;SHA&quot; fileext=&quot;asc&quot;/&gt;</pre>
Generates a SHA checksum for foo.bar and stores the checksum in the destination file
foo.bar.asc.  foo.bar.asc is overwritten only if foo.bar is newer than itself.

<p><b>Example 6</b></p>
<pre>
&lt;checksum file=&quot;foo.bar&quot; property=&quot;${md5}&quot; verifyProperty=&quot;isEqual&quot;/&gt;
</pre>
Generates a MD5 checksum for foo.bar, compares it against the value of the property
md5, and sets isEqual to either true or false, depending upon the result.

<p><b>Example 7</b></p>
<pre>
&lt;checksum&gt;
  &lt;fileset dir=&quot;.&quot;&gt;
    &lt;include name=&quot;foo*&quot;/&gt;
  &lt;/fileset&gt;
&lt;/checksum&gt;
</pre>
Works just like Example 1, but generates a .MD5 file for every file that begins with the name foo.

<p><b>Example 8</b></p>
<pre>
&lt;condition property=&quot;isChecksumEqual&quot;&gt;
  &lt;checksum&gt;
    &lt;fileset dir=&quot;.&quot;&gt;
      &lt;include name=&quot;foo.bar&quot;/&gt;
    &lt;/fileset&gt;
  &lt;/checksum&gt;
&lt;/condition&gt;
</pre>
Works like Example 4, but only sets isChecksumEqual to true, if the
checksum matches - it will never be set to false.  This example
demonstrates use with the Condition task.


<h3>Note:</h3>
When working with more than one file, if condition and/or verifyproperty is used,
the result will be true only if the checksums matched correctly for all files being
considered.

<hr><p align="center">Copyright &copy; 2001-2003 Apache Software Foundation. All rights
Reserved.</p>

</body>
</html>