src/applications/diffusion/protocol/DiffusionMercurialWireProtocol.php

   1 <?php
   2
   3 final class DiffusionMercurialWireProtocol extends Phobject {
   4
   5   public static function getCommandArgs($command) {
   6     // We need to enumerate all of the Mercurial wire commands because the
   7     // argument encoding varies based on the command. "Why?", you might ask,
   8     // "Why would you do this?".
   9
  10     $commands = array(
  11       'batch' => array('cmds', '*'),
  12       'between' => array('pairs'),
  13       'branchmap' => array(),
  14       'branches' => array('nodes'),
  15       'capabilities' => array(),
  16       'changegroup' => array('roots'),
  17       'changegroupsubset' => array('bases heads'),
  18       'debugwireargs' => array('one two *'),
  19       'getbundle' => array('*'),
  20       'heads' => array(),
  21       'hello' => array(),
  22       'known' => array('nodes', '*'),
  23       'listkeys' => array('namespace'),
  24       'lookup' => array('key'),
  25       'pushkey' => array('namespace', 'key', 'old', 'new'),
  26       'protocaps' => array('caps'),
  27       'stream_out' => array(''),
  28       'unbundle' => array('heads'),
  29     );
  30
  31     if (!isset($commands[$command])) {
  32       throw new Exception(
  33         pht(
  34           'Unknown Mercurial command "%s"!',
  35           $command));
  36     }
  37
  38     return $commands[$command];
  39   }
  40
  41   public static function isReadOnlyCommand($command) {
  42     $read_only = array(
  43       'between' => true,
  44       'branchmap' => true,
  45       'branches' => true,
  46       'capabilities' => true,
  47       'changegroup' => true,
  48       'changegroupsubset' => true,
  49       'debugwireargs' => true,
  50       'getbundle' => true,
  51       'heads' => true,
  52       'hello' => true,
  53       'known' => true,
  54       'listkeys' => true,
  55       'lookup' => true,
  56       'protocaps' => true,
  57       'stream_out' => true,
  58     );
  59
  60     // Notably, the write commands are "pushkey" and "unbundle". The
  61     // "batch" command is theoretically read only, but we require explicit
  62     // analysis of the actual commands.
  63
  64     return isset($read_only[$command]);
  65   }
  66
  67   public static function isReadOnlyBatchCommand($cmds) {
  68     if (!strlen($cmds)) {
  69       // We expect a "batch" command to always have a "cmds" string, so err
  70       // on the side of caution and throw if we don't get any data here. This
  71       // either indicates a mangled command from the client or a programming
  72       // error in our code.
  73       throw new Exception(pht("Expected nonempty '%s' specification!", 'cmds'));
  74     }
  75
  76     // For "batch" we get a "cmds" argument like:
  77     //
  78     //   heads ;known nodes=
  79     //
  80     // We need to examine the commands (here, "heads" and "known") to make sure
  81     // they're all read-only.
  82
  83     // NOTE: Mercurial has some code to escape semicolons, but it does not
  84     // actually function for command separation. For example, these two batch
  85     // commands will produce completely different results (the former will run
  86     // the lookup; the latter will fail with a parser error):
  87     //
  88     //  lookup key=a:xb;lookup key=z* 0
  89     //  lookup key=a:;b;lookup key=z* 0
  90     //               ^
  91     //               |
  92     //               +-- Note semicolon.
  93     //
  94     // So just split unconditionally.
  95
  96     $cmds = explode(';', $cmds);
  97     foreach ($cmds as $sub_cmd) {
  98       $name = head(explode(' ', $sub_cmd, 2));
  99       if (!self::isReadOnlyCommand($name)) {
 100         return false;
 101       }
 102     }
 103
 104     return true;
 105   }
 106
 107   /** If the server version is running 3.4+ it will respond
 108    * with 'bundle2' capability in the format of "bundle2=(url-encoding)".
 109    * Until we manage to properly package up bundles to send back we
 110    * disallow the client from knowing we speak bundle2 by removing it
 111    * from the capabilities listing.
 112    *
 113    * The format of the capabilities string is: "a space separated list
 114    * of strings representing what commands the server supports"
 115    * @link https://www.mercurial-scm.org/wiki/CommandServer#Protocol
 116    *
 117    * @param string  $capabilities - The string of capabilities to
 118    *   strip the bundle2 capability from. This is expected to be
 119    *   the space-separated list of strings resulting from the
 120    *   querying the 'capabilities' command.
 121    *
 122    * @return string  The resulting space-separated list of capabilities
 123    *   which no longer contains the 'bundle2' capability. This is meant
 124    *   to replace the original $body to send back to client.
 125    */
 126   public static function filterBundle2Capability($capabilities) {
 127     $parts = explode(' ', $capabilities);
 128     foreach ($parts as $key => $part) {
 129       if (preg_match('/^bundle2=/', $part)) {
 130         unset($parts[$key]);
 131         break;
 132       }
 133     }
 134     return implode(' ', $parts);
 135   }
 136
 137 }