Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/IPython/core/displayhook.py: 21%
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« prev ^ index » next coverage.py v7.4.4, created at 2024-04-20 06:09 +0000
1# -*- coding: utf-8 -*-
2"""Displayhook for IPython.
4This defines a callable class that IPython uses for `sys.displayhook`.
5"""
7# Copyright (c) IPython Development Team.
8# Distributed under the terms of the Modified BSD License.
10import builtins as builtin_mod
11import sys
12import io as _io
13import tokenize
15from traitlets.config.configurable import Configurable
16from traitlets import Instance, Float
17from warnings import warn
19# TODO: Move the various attributes (cache_size, [others now moved]). Some
20# of these are also attributes of InteractiveShell. They should be on ONE object
21# only and the other objects should ask that one object for their values.
23class DisplayHook(Configurable):
24 """The custom IPython displayhook to replace sys.displayhook.
26 This class does many things, but the basic idea is that it is a callable
27 that gets called anytime user code returns a value.
28 """
30 shell = Instance('IPython.core.interactiveshell.InteractiveShellABC',
31 allow_none=True)
32 exec_result = Instance('IPython.core.interactiveshell.ExecutionResult',
33 allow_none=True)
34 cull_fraction = Float(0.2)
36 def __init__(self, shell=None, cache_size=1000, **kwargs):
37 super(DisplayHook, self).__init__(shell=shell, **kwargs)
38 cache_size_min = 3
39 if cache_size <= 0:
40 self.do_full_cache = 0
41 cache_size = 0
42 elif cache_size < cache_size_min:
43 self.do_full_cache = 0
44 cache_size = 0
45 warn('caching was disabled (min value for cache size is %s).' %
46 cache_size_min,stacklevel=3)
47 else:
48 self.do_full_cache = 1
50 self.cache_size = cache_size
52 # we need a reference to the user-level namespace
53 self.shell = shell
55 self._,self.__,self.___ = '','',''
57 # these are deliberately global:
58 to_user_ns = {'_':self._,'__':self.__,'___':self.___}
59 self.shell.user_ns.update(to_user_ns)
61 @property
62 def prompt_count(self):
63 return self.shell.execution_count
65 #-------------------------------------------------------------------------
66 # Methods used in __call__. Override these methods to modify the behavior
67 # of the displayhook.
68 #-------------------------------------------------------------------------
70 def check_for_underscore(self):
71 """Check if the user has set the '_' variable by hand."""
72 # If something injected a '_' variable in __builtin__, delete
73 # ipython's automatic one so we don't clobber that. gettext() in
74 # particular uses _, so we need to stay away from it.
75 if '_' in builtin_mod.__dict__:
76 try:
77 user_value = self.shell.user_ns['_']
78 if user_value is not self._:
79 return
80 del self.shell.user_ns['_']
81 except KeyError:
82 pass
84 def quiet(self):
85 """Should we silence the display hook because of ';'?"""
86 # do not print output if input ends in ';'
88 try:
89 cell = self.shell.history_manager.input_hist_parsed[-1]
90 except IndexError:
91 # some uses of ipshellembed may fail here
92 return False
94 return self.semicolon_at_end_of_expression(cell)
96 @staticmethod
97 def semicolon_at_end_of_expression(expression):
98 """Parse Python expression and detects whether last token is ';'"""
100 sio = _io.StringIO(expression)
101 tokens = list(tokenize.generate_tokens(sio.readline))
103 for token in reversed(tokens):
104 if token[0] in (tokenize.ENDMARKER, tokenize.NL, tokenize.NEWLINE, tokenize.COMMENT):
105 continue
106 if (token[0] == tokenize.OP) and (token[1] == ';'):
107 return True
108 else:
109 return False
111 def start_displayhook(self):
112 """Start the displayhook, initializing resources."""
113 pass
115 def write_output_prompt(self):
116 """Write the output prompt.
118 The default implementation simply writes the prompt to
119 ``sys.stdout``.
120 """
121 # Use write, not print which adds an extra space.
122 sys.stdout.write(self.shell.separate_out)
123 outprompt = 'Out[{}]: '.format(self.shell.execution_count)
124 if self.do_full_cache:
125 sys.stdout.write(outprompt)
127 def compute_format_data(self, result):
128 """Compute format data of the object to be displayed.
130 The format data is a generalization of the :func:`repr` of an object.
131 In the default implementation the format data is a :class:`dict` of
132 key value pair where the keys are valid MIME types and the values
133 are JSON'able data structure containing the raw data for that MIME
134 type. It is up to frontends to determine pick a MIME to to use and
135 display that data in an appropriate manner.
137 This method only computes the format data for the object and should
138 NOT actually print or write that to a stream.
140 Parameters
141 ----------
142 result : object
143 The Python object passed to the display hook, whose format will be
144 computed.
146 Returns
147 -------
148 (format_dict, md_dict) : dict
149 format_dict is a :class:`dict` whose keys are valid MIME types and values are
150 JSON'able raw data for that MIME type. It is recommended that
151 all return values of this should always include the "text/plain"
152 MIME type representation of the object.
153 md_dict is a :class:`dict` with the same MIME type keys
154 of metadata associated with each output.
156 """
157 return self.shell.display_formatter.format(result)
159 # This can be set to True by the write_output_prompt method in a subclass
160 prompt_end_newline = False
162 def write_format_data(self, format_dict, md_dict=None) -> None:
163 """Write the format data dict to the frontend.
165 This default version of this method simply writes the plain text
166 representation of the object to ``sys.stdout``. Subclasses should
167 override this method to send the entire `format_dict` to the
168 frontends.
170 Parameters
171 ----------
172 format_dict : dict
173 The format dict for the object passed to `sys.displayhook`.
174 md_dict : dict (optional)
175 The metadata dict to be associated with the display data.
176 """
177 if 'text/plain' not in format_dict:
178 # nothing to do
179 return
180 # We want to print because we want to always make sure we have a
181 # newline, even if all the prompt separators are ''. This is the
182 # standard IPython behavior.
183 result_repr = format_dict['text/plain']
184 if '\n' in result_repr:
185 # So that multi-line strings line up with the left column of
186 # the screen, instead of having the output prompt mess up
187 # their first line.
188 # We use the prompt template instead of the expanded prompt
189 # because the expansion may add ANSI escapes that will interfere
190 # with our ability to determine whether or not we should add
191 # a newline.
192 if not self.prompt_end_newline:
193 # But avoid extraneous empty lines.
194 result_repr = '\n' + result_repr
196 try:
197 print(result_repr)
198 except UnicodeEncodeError:
199 # If a character is not supported by the terminal encoding replace
200 # it with its \u or \x representation
201 print(result_repr.encode(sys.stdout.encoding,'backslashreplace').decode(sys.stdout.encoding))
203 def update_user_ns(self, result):
204 """Update user_ns with various things like _, __, _1, etc."""
206 # Avoid recursive reference when displaying _oh/Out
207 if self.cache_size and result is not self.shell.user_ns['_oh']:
208 if len(self.shell.user_ns['_oh']) >= self.cache_size and self.do_full_cache:
209 self.cull_cache()
211 # Don't overwrite '_' and friends if '_' is in __builtin__
212 # (otherwise we cause buggy behavior for things like gettext). and
213 # do not overwrite _, __ or ___ if one of these has been assigned
214 # by the user.
215 update_unders = True
216 for unders in ['_'*i for i in range(1,4)]:
217 if not unders in self.shell.user_ns:
218 continue
219 if getattr(self, unders) is not self.shell.user_ns.get(unders):
220 update_unders = False
222 self.___ = self.__
223 self.__ = self._
224 self._ = result
226 if ('_' not in builtin_mod.__dict__) and (update_unders):
227 self.shell.push({'_':self._,
228 '__':self.__,
229 '___':self.___}, interactive=False)
231 # hackish access to top-level namespace to create _1,_2... dynamically
232 to_main = {}
233 if self.do_full_cache:
234 new_result = '_%s' % self.prompt_count
235 to_main[new_result] = result
236 self.shell.push(to_main, interactive=False)
237 self.shell.user_ns['_oh'][self.prompt_count] = result
239 def fill_exec_result(self, result):
240 if self.exec_result is not None:
241 self.exec_result.result = result
243 def log_output(self, format_dict):
244 """Log the output."""
245 if 'text/plain' not in format_dict:
246 # nothing to do
247 return
248 if self.shell.logger.log_output:
249 self.shell.logger.log_write(format_dict['text/plain'], 'output')
250 self.shell.history_manager.output_hist_reprs[self.prompt_count] = \
251 format_dict['text/plain']
253 def finish_displayhook(self):
254 """Finish up all displayhook activities."""
255 sys.stdout.write(self.shell.separate_out2)
256 sys.stdout.flush()
258 def __call__(self, result=None):
259 """Printing with history cache management.
261 This is invoked every time the interpreter needs to print, and is
262 activated by setting the variable sys.displayhook to it.
263 """
264 self.check_for_underscore()
265 if result is not None and not self.quiet():
266 self.start_displayhook()
267 self.write_output_prompt()
268 format_dict, md_dict = self.compute_format_data(result)
269 self.update_user_ns(result)
270 self.fill_exec_result(result)
271 if format_dict:
272 self.write_format_data(format_dict, md_dict)
273 self.log_output(format_dict)
274 self.finish_displayhook()
276 def cull_cache(self):
277 """Output cache is full, cull the oldest entries"""
278 oh = self.shell.user_ns.get('_oh', {})
279 sz = len(oh)
280 cull_count = max(int(sz * self.cull_fraction), 2)
281 warn('Output cache limit (currently {sz} entries) hit.\n'
282 'Flushing oldest {cull_count} entries.'.format(sz=sz, cull_count=cull_count))
284 for i, n in enumerate(sorted(oh)):
285 if i >= cull_count:
286 break
287 self.shell.user_ns.pop('_%i' % n, None)
288 oh.pop(n, None)
291 def flush(self):
292 if not self.do_full_cache:
293 raise ValueError("You shouldn't have reached the cache flush "
294 "if full caching is not enabled!")
295 # delete auto-generated vars from global namespace
297 for n in range(1,self.prompt_count + 1):
298 key = '_'+repr(n)
299 try:
300 del self.shell.user_ns[key]
301 except: pass
302 # In some embedded circumstances, the user_ns doesn't have the
303 # '_oh' key set up.
304 oh = self.shell.user_ns.get('_oh', None)
305 if oh is not None:
306 oh.clear()
308 # Release our own references to objects:
309 self._, self.__, self.___ = '', '', ''
311 if '_' not in builtin_mod.__dict__:
312 self.shell.user_ns.update({'_':self._,'__':self.__,'___':self.___})
313 import gc
314 # TODO: Is this really needed?
315 # IronPython blocks here forever
316 if sys.platform != "cli":
317 gc.collect()
320class CapturingDisplayHook(object):
321 def __init__(self, shell, outputs=None):
322 self.shell = shell
323 if outputs is None:
324 outputs = []
325 self.outputs = outputs
327 def __call__(self, result=None):
328 if result is None:
329 return
330 format_dict, md_dict = self.shell.display_formatter.format(result)
331 self.outputs.append({ 'data': format_dict, 'metadata': md_dict })