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OCRmyPDF/src/ocrmypdf/_progressbar.py
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136 lines
3.8 KiB
Python

from typing import Protocol
from rich.console import Console
from rich.progress import (
BarColumn,
MofNCompleteColumn,
Progress,
TaskProgressColumn,
TextColumn,
TimeRemainingColumn,
)
from rich.table import Column
class ProgressBar(Protocol):
"""The protocol that OCRmyPDF expects progress bar classes to be compatible with.
In practice this could be used for any time of monitoring, not just a progress bar.
Calling the class should return a new progress bar object, which is activated
with ``__enter__`` and terminated with ``__exit__``. An update method is called
whenever the progress bar is updated. Progress bar objects will not be reused;
a new one will be created for each group of tasks.
The progress bar is held in the main process/thread and not updated by child
process/threads. When a child notifies the parent of completed work, the
parent updates the progress bar.
Progress bars should never write to ``sys.stdout``, or they will corrupt the
output if OCRmyPDF writes a PDF to standard output.
The type of events that OCRmyPDF reports to a progress bar may change in
minor releases.
"""
def __init__(
self,
*,
total: int | float | None,
desc: str | None,
unit: str | None,
disable: bool = False,
**kwargs,
):
"""Initialize a progress bar.
*total* indicates the total number of work units. If None, the total
number of work units is unknown. If *disable* is True, the progress bar
should be disabled. *unit* is a description of the work unit.
*desc* is a description of the overall task to be performed.
Unrecognized keyword arguments must be ignored, as the list of keyword
arguments may grow with time.
"""
def __enter__(self):
"""Enter a progress bar context."""
def __exit__(self, *args):
"""Exit a progress bar context."""
def update(self, n=1):
"""Update the progress bar by an increment.
For use within a progress bar context.
"""
class NullProgressBar:
"""Progress bar API that takes no actions."""
def __init__(self, **kwargs):
pass
def __enter__(self):
return self
def __exit__(self, exc_type, exc_value, traceback):
return False
def update(self, _arg=None):
return
class RichProgressBar:
"""Display progress bar using rich."""
def __init__(
self,
*,
console: Console,
desc: str,
total: float | None = None,
unit: str | None = None,
unit_scale: float | None = 1.0,
disable: bool = False,
**kwargs,
):
self.progress = Progress(
TextColumn(
"[progress.description]{task.description}",
table_column=Column(min_width=20),
),
BarColumn(),
TaskProgressColumn(),
MofNCompleteColumn(),
TimeRemainingColumn(),
console=console,
auto_refresh=True,
redirect_stderr=True,
redirect_stdout=False,
disable=disable,
**kwargs,
)
self.unit_scale = unit_scale
self.progress_bar = self.progress.add_task(
desc,
total=total * self.unit_scale
if total is not None and self.unit_scale is not None
else None,
unit=unit,
)
def __enter__(self):
self.progress.start()
return self
def __exit__(self, exc_type, exc_value, traceback):
self.progress.refresh()
self.progress.stop()
return False
def update(self, value=None):
advance = self.unit_scale if value is None else value
self.progress.update(self.progress_bar, advance=advance)