KParts

readonlypart.h
1 /*
2  This file is part of the KDE project
3  SPDX-FileCopyrightText: 1999 Simon Hausmann <hausmann@kde.org>
4  SPDX-FileCopyrightText: 1999 David Faure <faure@kde.org>
5 
6  SPDX-License-Identifier: LGPL-2.0-or-later
7 */
8 
9 #ifndef _KPARTS_READONLYPART_H
10 #define _KPARTS_READONLYPART_H
11 
12 #include <kparts/part.h>
13 
14 #include <QUrl>
15 
16 class KJob;
17 namespace KIO
18 {
19 class Job;
20 }
21 
22 namespace KParts
23 {
24 class ReadOnlyPartPrivate;
25 class NavigationExtension;
26 class OpenUrlArguments;
27 
28 /**
29  * @class ReadOnlyPart readonlypart.h <KParts/ReadOnlyPart>
30  *
31  * @short Base class for any "viewer" part.
32  *
33  * This class takes care of network transparency for you,
34  * in the simplest way (downloading to a temporary file, then letting the part
35  * load from the temporary file).
36  * To use the built-in network transparency, you only need to implement
37  * openFile(), not openUrl().
38  *
39  * To implement network transparency differently (e.g. for progressive loading,
40  * like a web browser does for instance), or to prevent network transparency
41  * (but why would you do that?), you can override openUrl().
42  *
43  * An application using KParts can use the signals to show feedback while
44  * the URL is being loaded.
45  *
46  * ReadOnlyPart handles the window caption by setting it to the current URL
47  * (set in openUrl(), and each time the part is activated).
48  * If you want another caption, set it in openFile() and,
49  * if the part might ever be used with a part manager, in guiActivateEvent().
50  */
51 class KPARTS_EXPORT ReadOnlyPart : public Part
52 {
53  Q_OBJECT
54 
55  Q_PROPERTY(QUrl url READ url)
56 
57  KPARTS_DECLARE_PRIVATE(ReadOnlyPart)
58 
59 public:
60  /**
61  * Constructor.
62  * See also Part for the setXXX methods to call.
63  */
64  explicit ReadOnlyPart(QObject *parent = nullptr, const KPluginMetaData &data = {});
65 
66  /**
67  * Destructor.
68  */
69  ~ReadOnlyPart() override;
70 
71  /**
72  * Call this to turn off the progress info dialog used by
73  * the internal KIO job. Use this if you provide another way
74  * of displaying progress info (e.g. a statusbar), using the
75  * signals emitted by this class, and/or those emitted by
76  * the job given by started().
77  */
78  void setProgressInfoEnabled(bool show);
79 
80  /**
81  * Returns whether the part shows the progress info dialog used by the internal
82  * KIO job.
83  */
84  bool isProgressInfoEnabled() const;
85 
86 public Q_SLOTS:
87  /**
88  * Only reimplement this if you don't want the network transparency support
89  * to download from the URL into a temporary file (when the URL isn't local).
90  * Otherwise, reimplement openFile() only.
91  *
92  * If you reimplement it, don't forget to set the caption, usually with
93  * @code
94  * Q_EMIT setWindowCaption( url.toDisplayString() );
95  * @endcode
96  * and also, if the URL refers to a local file, resolve it to a
97  * local path and call setLocalFilePath().
98  */
99  virtual bool openUrl(const QUrl &url);
100 
101 public:
102  /**
103  * Returns the URL currently opened in (or being opened by) this part.
104  * @note The URL is not cleared if openUrl() fails to load the URL.
105  * Call closeUrl() if you need to explicitly reset it.
106  *
107  * @return The current URL.
108  */
109  QUrl url() const;
110 
111  /**
112  * Called when closing the current URL (for example, a document), for instance
113  * when switching to another URL (note that openUrl() calls it
114  * automatically in this case).
115  * If the current URL is not fully loaded yet, aborts loading.
116  * Deletes the temporary file used when the URL is remote.
117  * Resets the current url() to QUrl().
118  * @return always true, but the return value exists for reimplementations
119  */
120  virtual bool closeUrl();
121 
122  /**
123  * This convenience method returns the NavigationExtension for this part,
124  * or @c nullptr if there isn't one.
125  */
126  NavigationExtension *navigationExtension() const;
127 
128  /**
129  * Sets the arguments to use for the next openUrl() call.
130  */
131  void setArguments(const OpenUrlArguments &arguments);
132  // TODO to avoid problems with the case where the loading fails, this could also be a openUrl() argument (heavy porting!).
133  // However we need to have setArguments in any case for updated made by the part, see e.g. KHTMLPart::openUrl.
134  // Well, maybe we should have setArguments (affects next openurl call) and updateArguments?
135 
136  /**
137  * @return the arguments that were used to open this URL.
138  */
139  OpenUrlArguments arguments() const;
140 
141 public:
142  /**
143  * Initiate sending data to this part.
144  * This is an alternative to openUrl(), which allows the user of the part
145  * to load the data itself, and send it progressively to the part.
146  *
147  * @param mimeType the type of data that is going to be sent to this part.
148  * @param url the URL representing this data. Although not directly used,
149  * every ReadOnlyPart has a URL (see url()), so this simply sets it.
150  * @return true if the part supports progressive loading and accepts data, false otherwise.
151  */
152  bool openStream(const QString &mimeType, const QUrl &url);
153 
154  /**
155  * Send some data to the part. openStream must have been called previously,
156  * and must have returned true.
157  * @return true if the data was accepted by the part. If false is returned,
158  * the application should stop sending data, and doesn't have to call closeStream.
159  */
160  bool writeStream(const QByteArray &data);
161 
162  /**
163  * Terminate the sending of data to the part.
164  * With some data types (text, html...) closeStream might never actually be called,
165  * in the case of continuous streams, for instance plain text or HTML data.
166  */
167  bool closeStream();
168 
169 #ifdef K_DOXYGEN
170 protected: // are parsed by doxygen (kapidox/ecm_add_qch): unhide for doxygen configured to skip private methods
171 #else
172 private: // Makes no sense for inherited classes to call those. But make it protected there.
173 #endif // K_DOXYGEN
174 
175  /**
176  * Called by openStream to initiate sending of data.
177  * Parts which implement progress loading should check the @p mimeType
178  * parameter, and return true if they can accept a data stream of that type.
179  */
180  virtual bool doOpenStream(const QString &mimeType)
181  {
182  Q_UNUSED(mimeType);
183  return false;
184  }
185  /**
186  * Receive some data from the hosting application.
187  * In this method the part should attempt to display the data progressively.
188  * With some data types (text, html...) closeStream might never actually be called,
189  * in the case of continuous streams. This can't happen with e.g. images.
190  */
191  virtual bool doWriteStream(const QByteArray &data)
192  {
193  Q_UNUSED(data);
194  return false;
195  }
196  /**
197  * This is called by closeStream(), to indicate that all the data has been sent.
198  * Parts should ensure that all of the data is displayed at this point.
199  * @return whether the data could be displayed correctly.
200  */
201  virtual bool doCloseStream()
202  {
203  return false;
204  }
205 
206 Q_SIGNALS:
207  /**
208  * The part emits this when starting to load data.
209  * If using a KIO::Job, it provides the @p job so that
210  * progress information can be shown. Otherwise, @p job is @c nullptr.
211  **/
212  void started(KIO::Job *job);
213 
214  /**
215  * Emit this when you have completed loading data.
216  * Hosting applications will want to know when the process of loading the data
217  * is finished, so that they can access the data when everything is loaded.
218  **/
219  void completed();
220 
221  /**
222  * This signal is similar to the @c KParts::ReadOnlyPart::completed() signal
223  * except it is only emitted if there is still a pending action to be executed
224  * on a delayed timer.
225  *
226  * An example of this is the meta-refresh tags on web pages used to reload/redirect
227  * after a certain period of time. This signal is useful if you want to give the
228  * user the ability to cancel such pending actions.
229  *
230  * @since 5.81
231  */
232  void completedWithPendingAction();
233 
234  /**
235  * Emit this if loading is canceled by the user or by an error.
236  * @param errMsg the error message, empty if the user canceled the loading voluntarily.
237  */
238  void canceled(const QString &errMsg);
239 
240  /**
241  * Emitted by the part when url() changes
242  * @since 4.10
243  */
244  void urlChanged(const QUrl &url);
245 
246 protected:
247  /**
248  * If the part uses the standard implementation of openUrl(),
249  * it must reimplement this to open the local file.
250  * The default implementation simply returns false.
251  *
252  * If this method returns true the part emits completed(),
253  * otherwise it emits canceled().
254  *
255  * @see completed(), canceled()
256  */
257  virtual bool openFile();
258 
259  /**
260  * @internal
261  */
262  void abortLoad();
263 
264  /**
265  * Reimplemented from Part, so that the window caption is set to
266  * the current URL (decoded) when the part is activated.
267  * This is the usual behavior in 99% of applications.
268  * Reimplement if you don't like it - test for event->activated()!
269  *
270  * @note This is done with GUIActivateEvent and not with
271  * PartActivateEvent because it's handled by the main window
272  * (which gets the event after the PartActivateEvent events have been sent).
273  */
274  void guiActivateEvent(GUIActivateEvent *event) override;
275 
276  /**
277  * Sets the URL associated with this part.
278  */
279  void setUrl(const QUrl &url);
280 
281  /**
282  * Returns the local file path associated with this part.
283  *
284  * @note The result will only be valid if openUrl() or
285  * setLocalFilePath() has previously been called.
286  */
287  QString localFilePath() const;
288 
289  /**
290  * Sets the local file path associated with this part.
291  */
292  void setLocalFilePath(const QString &localFilePath);
293 
294 protected:
295  KPARTS_NO_EXPORT ReadOnlyPart(ReadOnlyPartPrivate &dd, QObject *parent);
296 
297 private:
298  Q_DISABLE_COPY(ReadOnlyPart)
299 };
300 
301 } // namespace
302 
303 #endif
virtual bool doCloseStream()
This is called by closeStream(), to indicate that all the data has been sent.
Definition: readonlypart.h:201
virtual bool doOpenStream(const QString &mimeType)
Called by openStream to initiate sending of data.
Definition: readonlypart.h:180
This event is sent to a Part when its GUI has been activated or deactivated. This is related to PartA...
virtual bool doWriteStream(const QByteArray &data)
Receive some data from the hosting application.
Definition: readonlypart.h:191
Base class for parts.
Definition: part.h:56
Base class for any "viewer" part.
Definition: readonlypart.h:51
OpenUrlArguments is the set of arguments that specify how a URL should be opened by KParts::ReadOnlyP...
The KParts namespace,.
An extension to KParts::ReadOnlyPart, which allows a better integration of parts with browsers (in pa...
This file is part of the KDE documentation.
Documentation copyright © 1996-2024 The KDE developers.
Generated on Thu Feb 15 2024 03:48:58 by doxygen 1.8.17 written by Dimitri van Heesch, © 1997-2006

KDE's Doxygen guidelines are available online.