b2g/simulator/packages/subprocess/README.md@97036ab72558 (annotated)
b2g/simulator/packages/subprocess/README.md
Tue, 06 Jan 2015 21:39:09 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Tue, 06 Jan 2015 21:39:09 +0100
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
- permissions
- -rw-r--r--
Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
| michael@0 | 1 | <h2>What's that?</h2> |
| michael@0 | 2 | Simply package enigmail hard work on providing IPC feature in mozilla platform. |
| michael@0 | 3 | So we are able to launch child proccesses from javascript, |
| michael@0 | 4 | and in our case, from addon-sdk libraries :) |
| michael@0 | 5 | |
| michael@0 | 6 | <h2>Sample of code:</h2> |
| michael@0 | 7 | This object allows to start a process, and read/write data to/from it |
| michael@0 | 8 | using stdin/stdout/stderr streams. |
| michael@0 | 9 | Usage example: |
| michael@0 | 10 | |
| michael@0 | 11 | const subprocess = require("subprocess"); |
| michael@0 | 12 | var p = subprocess.call({ |
| michael@0 | 13 | command: '/bin/foo', |
| michael@0 | 14 | arguments: ['-v', 'foo'], |
| michael@0 | 15 | environment: [ "XYZ=abc", "MYVAR=def" ], |
| michael@0 | 16 | charset: 'UTF-8', |
| michael@0 | 17 | workdir: '/home/foo', |
| michael@0 | 18 | //stdin: "some value to write to stdin\nfoobar", |
| michael@0 | 19 | stdin: function(stdin) { |
| michael@0 | 20 | stdin.write("some value to write to stdin\nfoobar"); |
| michael@0 | 21 | stdin.close(); |
| michael@0 | 22 | }, |
| michael@0 | 23 | stdout: function(data) { |
| michael@0 | 24 | dump("got data on stdout:" + data + "\n"); |
| michael@0 | 25 | }, |
| michael@0 | 26 | stderr: function(data) { |
| michael@0 | 27 | dump("got data on stderr:" + data + "\n"); |
| michael@0 | 28 | }, |
| michael@0 | 29 | done: function(result) { |
| michael@0 | 30 | dump("process terminated with " + result.exitCode + "\n"); |
| michael@0 | 31 | }, |
| michael@0 | 32 | mergeStderr: false |
| michael@0 | 33 | }); |
| michael@0 | 34 | p.wait(); // wait for the subprocess to terminate |
| michael@0 | 35 | // this will block the main thread, |
| michael@0 | 36 | // only do if you can wait that long |
| michael@0 | 37 | |
| michael@0 | 38 | |
| michael@0 | 39 | Description of parameters: |
| michael@0 | 40 | -------------------------- |
| michael@0 | 41 | Apart from <command>, all arguments are optional. |
| michael@0 | 42 | |
| michael@0 | 43 | command: either a |nsIFile| object pointing to an executable file or a |
| michael@0 | 44 | String containing the platform-dependent path to an executable |
| michael@0 | 45 | file. |
| michael@0 | 46 | |
| michael@0 | 47 | arguments: optional string array containing the arguments to the command. |
| michael@0 | 48 | |
| michael@0 | 49 | environment: optional string array containing environment variables to pass |
| michael@0 | 50 | to the command. The array elements must have the form |
| michael@0 | 51 | "VAR=data". Please note that if environment is defined, it |
| michael@0 | 52 | replaces any existing environment variables for the subprocess. |
| michael@0 | 53 | |
| michael@0 | 54 | charset: Output is decoded with given charset and a string is returned. |
| michael@0 | 55 | If charset is undefined, "UTF-8" is used as default. |
| michael@0 | 56 | To get binary data, set this to null and the returned string |
| michael@0 | 57 | is not decoded in any way. |
| michael@0 | 58 | |
| michael@0 | 59 | workdir: optional; String containing the platform-dependent path to a |
| michael@0 | 60 | directory to become the current working directory of the subprocess. |
| michael@0 | 61 | |
| michael@0 | 62 | stdin: optional input data for the process to be passed on standard |
| michael@0 | 63 | input. stdin can either be a string or a function. |
| michael@0 | 64 | A |string| gets written to stdin and stdin gets closed; |
| michael@0 | 65 | A |function| gets passed an object with write and close function. |
| michael@0 | 66 | Please note that the write() function will return almost immediately; |
| michael@0 | 67 | data is always written asynchronously on a separate thread. |
| michael@0 | 68 | |
| michael@0 | 69 | stdout: an optional function that can receive output data from the |
| michael@0 | 70 | process. The stdout-function is called asynchronously; it can be |
| michael@0 | 71 | called mutliple times during the execution of a process. |
| michael@0 | 72 | At a minimum at each occurance of \n or \r. |
| michael@0 | 73 | Please note that null-characters might need to be escaped |
| michael@0 | 74 | with something like 'data.replace(/\0/g, "\\0");'. |
| michael@0 | 75 | |
| michael@0 | 76 | stderr: an optional function that can receive stderr data from the |
| michael@0 | 77 | process. The stderr-function is called asynchronously; it can be |
| michael@0 | 78 | called mutliple times during the execution of a process. Please |
| michael@0 | 79 | note that null-characters might need to be escaped with |
| michael@0 | 80 | something like 'data.replace(/\0/g, "\\0");'. |
| michael@0 | 81 | (on windows it only gets called once right now) |
| michael@0 | 82 | |
| michael@0 | 83 | done: optional function that is called when the process has terminated. |
| michael@0 | 84 | The exit code from the process available via result.exitCode. If |
| michael@0 | 85 | stdout is not defined, then the output from stdout is available |
| michael@0 | 86 | via result.stdout. stderr data is in result.stderr |
| michael@0 | 87 | |
| michael@0 | 88 | mergeStderr: optional boolean value. If true, stderr is merged with stdout; |
| michael@0 | 89 | no data will be provided to stderr. |
| michael@0 | 90 | |
| michael@0 | 91 | |
| michael@0 | 92 | Description of object returned by subprocess.call(...) |
| michael@0 | 93 | ------------------------------------------------------ |
| michael@0 | 94 | The object returned by subprocess.call offers a few methods that can be |
| michael@0 | 95 | executed: |
| michael@0 | 96 | |
| michael@0 | 97 | wait(): waits for the subprocess to terminate. It is not required to use |
| michael@0 | 98 | wait; done will be called in any case when the subprocess terminated. |
| michael@0 | 99 | |
| michael@0 | 100 | kill(hardKill): kill the subprocess. Any open pipes will be closed and |
| michael@0 | 101 | done will be called. |
| michael@0 | 102 | hardKill [ignored on Windows]: |
| michael@0 | 103 | - false: signal the process terminate (SIGTERM) |
| michael@0 | 104 | - true: kill the process (SIGKILL) |
| michael@0 | 105 | |
| michael@0 | 106 | |
| michael@0 | 107 | Other methods in subprocess |
| michael@0 | 108 | --------------------------- |
| michael@0 | 109 | |
| michael@0 | 110 | registerDebugHandler(functionRef): register a handler that is called to get |
| michael@0 | 111 | debugging information |
| michael@0 | 112 | registerLogHandler(functionRef): register a handler that is called to get error |
| michael@0 | 113 | messages |
| michael@0 | 114 | |
| michael@0 | 115 | example: |
| michael@0 | 116 | subprocess.registerLogHandler( function(s) { dump(s); } ); |
| michael@0 | 117 | |
| michael@0 | 118 | |
| michael@0 | 119 | <h2>Credits:</h2> |
| michael@0 | 120 | All enigmail team working on IPC component. |
| michael@0 | 121 | The Initial Developer of this code is Jan Gerber. |
| michael@0 | 122 | Portions created by Jan Gerber <j@mailb.org>, |
| michael@0 | 123 | Patrick Brunschwig (author of almost all code) <patrick@mozilla-enigmail.org>, |
| michael@0 | 124 | Ramalingam Saravanan (from enigmail team) <svn@xmlterm.org> |
