Diviner libphutil Tech Docs LinesOfALarge

abstract class LinesOfALarge
libphutil Technical Documentation (Filesystem)

Abstraction for processing large inputs without holding them in memory. This class implements line-oriented, buffered reads of some external stream, where a "line" is characterized by some delimiter character. This provides a straightforward interface for most large-input tasks, with relatively good performance.

If your stream is not large, it is generally more efficient (and certainly simpler) to read the entire stream first and then process it (e.g., with explode()).

This class is abstract. The concrete implementations available are:

LinesOfALargeFile, for reading large files; and
LinesOfALargeExecFuture, for reading large output from subprocesses.

For example:

foreach (new LinesOfALargeFile('/path/to/file.log') as $line) {
  // ...
}

By default, a line is delimited by "\n". The delimiting character is not returned. You can change the character with setDelimiter(). The last part of the file is returned as the last $line, even if it does not include a terminating character (if it does, the terminating character is stripped).

Tasks

Configuration

final public function setDelimiter($character) — Change the "line" delimiter character, which defaults to "\n". This is used to determine where each line ends.

Internals

abstract protected function willRewind() — Hook, called before @{method:rewind()}. Allows a concrete implementation to open resources or reset state.
abstract protected function readMore() — Called when the iterator needs more data. The subclass should return more data, or empty string to indicate end-of-stream.

Iterator Interface

final public function current()
final public function key()
final public function next()
final public function rewind()
final public function valid()

Other Methods

public function __get($name)
public function __set($name, $value)
private function throwOnAttemptedIteration()
public function getPhobjectClassConstant($key, $byte_limit) — Read the value of a class constant.

Methods

public function __get($name)
Inherited