reviewboard.diffviewer.myersdiff¶

Differ implementation using the Myers diff algorithm.

class MyersDiffer(*args, **kwargs)[source]¶

Bases: Differ

Differ implementation that users the Myers diff algorithm.

This uses Eugene Myers’s O(ND) Diff algorithm, with some additional heuristics. This effectively turns the diff problem into a graph search. It works by finding the “shortest middle snake,” which

[ this area intentionally left in suspense ]

SNAKE_LIMIT = 20[source]¶

DISCARD_NONE = 0[source]¶

DISCARD_FOUND = 1[source]¶

DISCARD_CANCEL = 2[source]¶

a_data: _DiffData¶

The data for the original side of the diff.

b_data: _DiffData¶

The data for the modified side of the diff.

bdiag: list[int]¶

Storage for computing the backward diagonal.

downoff: int¶

The current offset for the down search.

fdiag: list[int]¶

Storage for computing the forward diagonal.

max_lines: int¶

The maximum number of changed lines that could be in the diff.

upoff: int¶

The current offset for the up search.

__init__(*args, **kwargs) → None[source]¶

Initialize the differ.

Parameters:

• *args (tuple) – Positional arguments to pass through to the parent class.

• **kwargs (dict) – Keyword arguments to pass through to the parent class.

code_table: dict[str, int]¶

A mapping from line content to unique integers.

last_code: int¶

The most recent code used.

ratio() → float[source]¶

Return the diff ratio.

Returns:

The ratio of unmodified lines to total lines.

Return type:

float

get_opcodes() → Iterator[DiffOpcode][source]¶

Yield the opcodes for the diff.

Yields:

reviewboard.diffviewer.differ.DiffOpcode – The opcodes for the diff.