"""An IDLE extension to avoid having very long texts printed in the shell.
A common problem in IDLE's interactive shell is printing of large amounts of
text into the shell. This makes looking at the previous history difficult.
Worse, this can cause IDLE to become very slow, even to the point of being
completely unusable.
This extension will automatically replace long texts with a small button.
Double-clicking this button will remove it and insert the original text instead.
Middle-clicking will copy the text to the clipboard. Right-clicking will open
the text in a separate viewing window.
Additionally, any output can be manually "squeezed" by the user. This includes
output written to the standard error stream ("stderr"), such as exception
messages and their tracebacks.
"""
import re
import tkinter as tk
import tkinter.messagebox as tkMessageBox
from idlelib.config import idleConf
from idlelib.textview import view_text
from idlelib.tooltip import Hovertip
from idlelib import macosx
def count_lines_with_wrapping(s, linewidth=80):
"""Count the number of lines in a given string.
Lines are counted as if the string was wrapped so that lines are never over
linewidth characters long.
Tabs are considered tabwidth characters long.
"""
tabwidth = 8 # Currently always true in Shell.
pos = 0
linecount = 1
current_column = 0
for m in re.finditer(r"[\t\n]", s):
# Process the normal chars up to tab or newline.
numchars = m.start() - pos
pos += numchars
current_column += numchars
# Deal with tab or newline.
if s[pos] == '\n':
# Avoid the `current_column == 0` edge-case, and while we're
# at it, don't bother adding 0.
if current_column > linewidth:
# If the current column was exactly linewidth, divmod
# would give (1,0), even though a new line hadn't yet
# been started. The same is true if length is any exact
# multiple of linewidth. Therefore, subtract 1 before
# dividing a non-empty line.
linecount += (current_column - 1) // linewidth
linecount += 1
current_column = 0
else:
assert s[pos] == '\t'
current_column += tabwidth - (current_column % tabwidth)
# If a tab passes the end of the line, consider the entire
# tab as being on the next line.
if current_column > linewidth:
linecount += 1
current_column = tabwidth
pos += 1 # After the tab or newline.
# Process remaining chars (no more tabs or newlines).
current_column += len(s) - pos
# Avoid divmod(-1, linewidth).
if current_column > 0:
linecount += (current_column - 1) // linewidth
else:
# Text ended with newline; don't count an extra line after it.
linecount -= 1
return linecount
class ExpandingButton(tk.Button):
"""Class for the "squeezed" text buttons used by Squeezer
These buttons are displayed inside a Tk Text widget in place of text. A
user can then use the button to replace it with the original text, copy
the original text to the clipboard or view the original text in a separate
window.
Each button is tied to a Squeezer instance, and it knows to update the
Squeezer instance when it is expanded (and therefore removed).
"""
def __init__(self, s, tags, numoflines, squeezer):
self.s = s
self.tags = tags
self.numoflines = numoflines
self.squeezer = squeezer
self.editwin = editwin = squeezer.editwin
self.text = text = editwin.text
# The base Text widget is needed to change text before iomark.
self.base_text = editwin.per.bottom
line_plurality = "lines" if numoflines != 1 else "line"
button_text = f"Squeezed text ({numoflines} {line_plurality})."
tk.Button.__init__(self, text, text=button_text,
background="#FFFFC0", activebackground="#FFFFE0")
button_tooltip_text = (
"Double-click to expand, right-click for more options."
)
Hovertip(self, button_tooltip_text, hover_delay=80)
self.bind("<Double-Button-1>", self.expand)
if macosx.isAquaTk():
# AquaTk defines <2> as the right button, not <3>.
self.bind("<Button-2>", self.context_menu_event)
else:
self.bind("<Button-3>", self.context_menu_event)
self.selection_handle( # X windows only.
lambda offset, length: s[int(offset):int(offset) + int(length)])
self.is_dangerous = None
self.after_idle(self.set_is_dangerous)
def set_is_dangerous(self):
dangerous_line_len = 50 * self.text.winfo_width()
self.is_dangerous = (
self.numoflines > 1000 or
len(self.s) > 50000 or
any(
len(line_match.group(0)) >= dangerous_line_len
for line_match in re.finditer(r'[^\n]+', self.s)
)
)
def expand(self, event=None):
"""expand event handler
This inserts the original text in place of the button in the Text
widget, removes the button and updates the Squeezer instance.
If the original text is dangerously long, i.e. expanding it could
cause a performance degradation, ask the user for confirmation.
"""
if self.is_dangerous is None:
self.set_is_dangerous()
if self.is_dangerous:
confirm = tkMessageBox.askokcancel(
title="Expand huge output?",
message="\n\n".join([
"The squeezed output is very long: %d lines, %d chars.",
"Expanding it could make IDLE slow or unresponsive.",
"It is recommended to view or copy the output instead.",
"Really expand?"
]) % (self.numoflines, len(self.s)),
default=tkMessageBox.CANCEL,
parent=self.text)
if not confirm:
return "break"
self.base_text.insert(self.text.index(self), self.s, self.tags)
self.base_text.delete(self)
self.squeezer.expandingbuttons.remove(self)
def copy(self, event=None):
"""copy event handler
Copy the original text to the clipboard.
"""
self.clipboard_clear()
self.clipboard_append(self.s)
def view(self, event=None):
"""view event handler
View the original text in a separate text viewer window.
"""
view_text(self.text, "Squeezed Output Viewer", self.s,
modal=False, wrap='none')
rmenu_specs = (
# Item structure: (label, method_name).
('copy', 'copy'),
('view', 'view'),
)
def context_menu_event(self, event):
self.text.mark_set("insert", "@%d,%d" % (event.x, event.y))
rmenu = tk.Menu(self.text, tearoff=0)
for label, method_name in self.rmenu_specs:
rmenu.add_command(label=label, command=getattr(self, method_name))
rmenu.tk_popup(event.x_root, event.y_root)
return "break"
class Squeezer:
"""Replace long outputs in the shell with a simple button.
This avoids IDLE's shell slowing down considerably, and even becoming
completely unresponsive, when very long outputs are written.
"""
@classmethod
def reload(cls):
"""Load class variables from config."""
cls.auto_squeeze_min_lines = idleConf.GetOption(
"main", "PyShell", "auto-squeeze-min-lines",
type="int", default=50,
)
def __init__(self, editwin):
"""Initialize settings for Squeezer.
editwin is the shell's Editor window.
self.text is the editor window text widget.
self.base_test is the actual editor window Tk text widget, rather than
EditorWindow's wrapper.
self.expandingbuttons is the list of all buttons representing
"squeezed" output.
"""
self.editwin = editwin
self.text = text = editwin.text
# Get the base Text widget of the PyShell object, used to change
# text before the iomark. PyShell deliberately disables changing
# text before the iomark via its 'text' attribute, which is
# actually a wrapper for the actual Text widget. Squeezer,
# however, needs to make such changes.
self.base_text = editwin.per.bottom
# Twice the text widget's border width and internal padding;
# pre-calculated here for the get_line_width() method.
self.window_width_delta = 2 * (
int(text.cget('border')) +
int(text.cget('padx'))
)
self.expandingbuttons = []
# Replace the PyShell instance's write method with a wrapper,
# which inserts an ExpandingButton instead of a long text.
def mywrite(s, tags=(), write=editwin.write):
# Only auto-squeeze text which has just the "stdout" tag.
if tags != "stdout":
return write(s, tags)
# Only auto-squeeze text with at least the minimum
# configured number of lines.
auto_squeeze_min_lines = self.auto_squeeze_min_lines
# First, a very quick check to skip very short texts.
if len(s) < auto_squeeze_min_lines:
return write(s, tags)
# Now the full line-count check.
numoflines = self.count_lines(s)
if numoflines < auto_squeeze_min_lines:
return write(s, tags)
# Create an ExpandingButton instance.
expandingbutton = ExpandingButton(s, tags, numoflines, self)
# Insert the ExpandingButton into the Text widget.
text.mark_gravity("iomark", tk.RIGHT)
text.window_create("iomark", window=expandingbutton,
padx=3, pady=5)
text.see("iomark")
text.update()
text.mark_gravity("iomark", tk.LEFT)
# Add the ExpandingButton to the Squeezer's list.
self.expandingbuttons.append(expandingbutton)
editwin.write = mywrite
def count_lines(self, s):
"""Count the number of lines in a given text.
Before calculation, the tab width and line length of the text are
fetched, so that up-to-date values are used.
Lines are counted as if the string was wrapped so that lines are never
over linewidth characters long.
Tabs are considered tabwidth characters long.
"""
return count_lines_with_wrapping(s, self.editwin.width)
def squeeze_current_text_event(self, event):
"""squeeze-current-text event handler
Squeeze the block of text inside which contains the "insert" cursor.
If the insert cursor is not in a squeezable block of text, give the
user a small warning and do nothing.
"""
# Set tag_name to the first valid tag found on the "insert" cursor.
tag_names = self.text.tag_names(tk.INSERT)
for tag_name in ("stdout", "stderr"):
if tag_name in tag_names:
break
else:
# The insert cursor doesn't have a "stdout" or "stderr" tag.
self.text.bell()
return "break"
# Find the range to squeeze.
start, end = self.text.tag_prevrange(tag_name, tk.INSERT + "+1c")
s = self.text.get(start, end)
# If the last char is a newline, remove it from the range.
if len(s) > 0 and s[-1] == '\n':
end = self.text.index("%s-1c" % end)
s = s[:-1]
# Delete the text.
self.base_text.delete(start, end)
# Prepare an ExpandingButton.
numoflines = self.count_lines(s)
expandingbutton = ExpandingButton(s, tag_name, numoflines, self)
# insert the ExpandingButton to the Text
self.text.window_create(start, window=expandingbutton,
padx=3, pady=5)
# Insert the ExpandingButton to the list of ExpandingButtons,
# while keeping the list ordered according to the position of
# the buttons in the Text widget.
i = len(self.expandingbuttons)
while i > 0 and self.text.compare(self.expandingbuttons[i-1],
">", expandingbutton):
i -= 1
self.expandingbuttons.insert(i, expandingbutton)
return "break"
Squeezer.reload()
if __name__ == "__main__":
from unittest import main
main('idlelib.idle_test.test_squeezer', verbosity=2, exit=False)
# Add htest.
