qfileselector.cpp

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40 -

41 #include "qfileselector.h" -

42 #include "qfileselector_p.h" -

43 -

44 #include <QtCore/QFile> -

45 #include <QtCore/QDir> -

46 #include <QtCore/QMutex> -

47 #include <QtCore/QMutexLocker> -

48 #include <QtCore/QUrl> -

49 #include <QtCore/QFileInfo> -

50 #include <QtCore/QLocale> -

51 #include <QtCore/QDebug> -

52 -

53 QT_BEGIN_NAMESPACE -

54 -

55 //Environment variable to allow tooling full control of file selectors -

56 static const char env_override[] = "QT_NO_BUILTIN_SELECTORS"; -

57 -

58 static const ushort selectorIndicator = '+'; -

59 -

60 Q_GLOBAL_STATIC(QFileSelectorSharedData, sharedData); -

61 static QBasicMutex sharedDataMutex; -

62 -

63 QFileSelectorPrivate::QFileSelectorPrivate() -

64 : QObjectPrivate() -

65 { -

66 } -

67 -

68 /*! -

69 \class QFileSelector -

70 \inmodule QtCore -

71 \brief QFileSelector provides a convenient way of selecting file variants. -

72 \since 5.2 -

73 -

74 QFileSelector is a convenience for selecting file variants based on platform or device -

75 characteristics. This allows you to develop and deploy one codebase containing all the -

76 different variants more easily in some circumstances, such as when the correct variant cannot -

77 be determined during the deploy step. -

78 -

79 \section1 Using QFileSelector -

80 -

81 If you always use the same file you do not need to use QFileSelector. -

82 -

83 Consider the following example usage, where you want to use different settings files on -

84 different locales. You might select code between locales like this: -

85 -

86 \code -

87 QString defaultsBasePath = "data/"; -

88 QString defaultsPath = defaultsBasePath + "defaults.conf"; -

89 QString localizedPath = defaultsBasePath -

90 + QString("%1/defaults.conf").arg(QLocale().name()); -

91 if (QFile::exists(localizedPath)) -

92 defaultsPath = localizedPath; -

93 QFile defaults(defaultsPath); -

94 \endcode -

95 -

96 Similarly, if you want to pick a different data file based on target platform, -

97 your code might look something like this: -

98 \code -

99 QString defaultsPath = "data/defaults.conf"; -

100 #if defined(Q_OS_ANDROID) -

101 defaultsPath = "data/android/defaults.conf"; -

102 #elif defined(Q_OS_IOS) -

103 defaultsPath = "data/ios/defaults.conf"; -

104 #endif -

105 QFile defaults(defaultsPath); -

106 \endcode -

107 -

108 QFileSelector provides a convenient alternative to writing such boilerplate code, and in the -

109 latter case it allows you to start using an platform-specific configuration without a recompile. -

110 QFileSelector also allows for chaining of multiple selectors in a convenient way, for example -

111 selecting a different file only on certain combinations of platform and locale. For example, to -

112 select based on platform and/or locale, the code is as follows: -

113 -

114 \code -

115 QFileSelector selector; -

116 QFile defaultsFile(selector.select("data/defaults.conf")); -

117 \endcode -

118 -

119 The files to be selected are placed in directories named with a \c'+' and a selector name. In the above -

120 example you could have the platform configurations selected by placing them in the following locations: -

121 \code -

122 data/defaults.conf -

123 data/+android/defaults.conf -

124 data/+ios/+en_GB/defaults.conf -

125 \endcode -

126 -

127 To find selected files, QFileSelector looks in the same directory as the base file. If there are -

128 any directories of the form +<selector> with an active selector, QFileSelector will prefer a file -

129 with the same file name from that directory over the base file. These directories can be nested to -

130 check against multiple selectors, for example: -

131 \code -

132 images/background.png -

133 images/+android/+en_GB/background.png -

134 \endcode -

135 With those files available, you would select a different file on the android platform, -

136 but only if the locale was en_GB. -

137 -

138 QFileSelector will not attempt to select if the base file does not exist. For error handling in -

139 the case no valid selectors are present, it is recommended to have a default or error-handling -

140 file in the base file location even if you expect selectors to be present for all deployments. -

141 -

142 In a future version, some may be marked as deploy-time static and be moved during the -

143 deployment step as an optimization. As selectors come with a performance cost, it is -

144 recommended to avoid their use in circumstances involving performance-critical code. -

145 -

146 \section1 Adding Selectors -

147 -

148 Selectors normally available are -

149 \list -

150 \li platform, any of the following strings which match the platform the application is running -

151 on (list not exhaustive): android, ios, osx, darwin, mac, linux, wince, unix, windows. -

152 On Linux, if it can be determined, the name of the distribution too, like debian, -

153 fedora or opensuse. -

154 \li locale, same as QLocale().name(). -

155 \endlist -

156 -

157 Further selectors will be added from the \c QT_FILE_SELECTORS environment variable, which -

158 when set should be a set of comma separated selectors. Note that this variable will only be -

159 read once; selectors may not update if the variable changes while the application is running. -

160 The initial set of selectors are evaluated only once, on first use. -

161 -

162 You can also add extra selectors at runtime for custom behavior. These will be used in any -

163 future calls to select(). If the extra selectors list has been changed, calls to select() will -

164 use the new list and may return differently. -

165 -

166 \section1 Conflict Resolution when Multiple Selectors Apply -

167 -

168 When multiple selectors could be applied to the same file, the first matching selector is chosen. -

169 The order selectors are checked in are: -

170 -

171 \list 1 -

172 \li Selectors set via setExtraSelectors(), in the order they are in the list -

173 \li Selectors in the \c QT_FILE_SELECTORS environment variable, from left to right -

174 \li Locale -

175 \li Platform -

176 \endlist -

177 -

178 Here is an example involving multiple selectors matching at the same time. It uses platform -

179 selectors, plus an extra selector named "admin" is set by the application based on user -

180 credentials. The example is sorted so that the lowest matching file would be chosen if all -

181 selectors were present: -

182 -

183 \code -

184 images/background.png -

185 images/+linux/background.png -

186 images/+windows/background.png -

187 images/+admin/background.png -

188 images/+admin/+linux/background.png -

189 \endcode -

190 -

191 Because extra selectors are checked before platform the \c{+admin/background.png} will be chosen -

192 on Windows when the admin selector is set, and \c{+windows/background.png} will be chosen on -

193 Windows when the admin selector is not set. On Linux, the \c{+admin/+linux/background.png} will be -

194 chosen when admin is set, and the \c{+linux/background.png} when it is not. -

195 -

196 */ -

197 -

198 /*! -

199 Create a QFileSelector instance. This instance will have the same static selectors as other -

200 QFileSelector instances, but its own set of extra selectors. -

201 -

202 If supplied, it will have the given QObject \a parent. -

203 */ -

204 QFileSelector::QFileSelector(QObject *parent) -

205 : QObject(*(new QFileSelectorPrivate()), parent) -

206 { -

207 } -

208 -

209 /*! -

210 Destroys this selector instance. -

211 */ -

212 QFileSelector::~QFileSelector() -

213 { -

214 } -

215 -

216 /*! -

217 This function returns the selected version of the path, based on the conditions at runtime. -

218 If no selectable files are present, returns the original \a filePath. -

219 -

220 If the original file does not exist, the original \a filePath is returned. This means that you -

221 must have a base file to fall back on, you cannot have only files in selectable sub-directories. -

222 -

223 See the class overview for the selection algorithm. -

224 */ -

225 QString QFileSelector::select(const QString &filePath) const -

226 { -

227 Q_D(const QFileSelector); -

228 return d->select(filePath); -

229 } -

230 -

231 static bool isLocalScheme(const QString &file) -

232 { -

233 bool local = file == QLatin1String("qrc"); -

234 #ifdef Q_OS_ANDROID -

235 local |= file == QLatin1String("assets"); -

236 #endif -

237 return local; -

238 } -

239 -

240 /*! -

241 This is a convenience version of select operating on QUrl objects. If the scheme is not file or qrc, -

242 \a filePath is returned immediately. Otherwise selection is applied to the path of \a filePath -

243 and a QUrl is returned with the selected path and other QUrl parts the same as \a filePath. -

244 -

245 See the class overview for the selection algorithm. -

246 */ -

247 QUrl QFileSelector::select(const QUrl &filePath) const -

248 { -

249 Q_D(const QFileSelector); -

250 if (!isLocalScheme(filePath.scheme()) && !filePath.isLocalFile()) -

251 return filePath; -

252 QUrl ret(filePath); -

253 if (isLocalScheme(filePath.scheme())) { -

254 QLatin1String scheme(":"); -

255 #ifdef Q_OS_ANDROID -

256 // use other scheme because ":" means "qrc" here -

257 if (filePath.scheme() == QLatin1String("assets")) -

258 scheme = QLatin1String("assets:"); -

259 #endif -

260 -

261 QString equivalentPath = scheme + filePath.path(); -

262 QString selectedPath = d->select(equivalentPath); -

263 ret.setPath(selectedPath.remove(0, scheme.size())); -

264 } else { -

265 ret = QUrl::fromLocalFile(d->select(ret.toLocalFile())); -

266 } -

267 return ret; -

268 } -

269 -

270 static QString selectionHelper(const QString &path, const QString &fileName, const QStringList &selectors) -

271 { -

272 /* selectionHelper does a depth-first search of possible selected files. Because there is strict -

273 selector ordering in the API, we can stop checking as soon as we find the file in a directory -

274 which does not contain any other valid selector directories. -

275 */ -

276 Q_ASSERT(path.isEmpty() || path.endsWith(QLatin1Char('/'))); -

277 -

278 foreachfor (const QString &s ,: selectors) { -

279 QString prospectiveBase = path + QLatin1Char(selectorIndicator) + s + QLatin1Char('/'); -

280 QStringList remainingSelectors = selectors; -

281 remainingSelectors.removeAll(s); -

282

if (!QDir(prospectiveBase).exists())

!QDir(prospect...Base).exists()	Description
TRUE	evaluated 95 times by 1 test Evaluated by: tst_QFileSelector
FALSE	evaluated 23 times by 1 test Evaluated by: tst_QFileSelector

23-95

283

continue;

executed 95 times by 1 test: continue;

Executed by:

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284 QString prospectiveFile = selectionHelper(prospectiveBase, fileName, remainingSelectors); -

285

if (!prospectiveFile.isEmpty())

!prospectiveFile.isEmpty()	Description
TRUE	evaluated 19 times by 1 test Evaluated by: tst_QFileSelector
FALSE	evaluated 4 times by 1 test Evaluated by: tst_QFileSelector

4-19

286

return prospectiveFile;

executed 19 times by 1 test: return prospectiveFile;

Executed by:

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287

}

executed 4 times by 1 test: end of block

Executed by:

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288 -

289 // If we reach here there were no successful files found at a lower level in this branch, so we -

290 // should check this level as a potential result. -

291

if (!QFile::exists(path + fileName))

!QFile::exists...th + fileName)	Description
TRUE	evaluated 4 times by 1 test Evaluated by: tst_QFileSelector
FALSE	evaluated 20 times by 1 test Evaluated by: tst_QFileSelector

4-20

292

return QString();

executed 4 times by 1 test: return QString();

Executed by:

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293

return path + fileName;

executed 20 times by 1 test: return path + fileName;

Executed by:

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294 } -

295 -

296 QString QFileSelectorPrivate::select(const QString &filePath) const -

297 { -

298 Q_Q(const QFileSelector); -

299 QFileInfo fi(filePath); -

300 // If file doesn't exist, don't select -

301 if (!fi.exists()) -

302 return filePath; -

303 -

304 QString ret = selectionHelper(fi.path().isEmpty() ? QString() : fi.path() + QLatin1Char('/'), -

305 fi.fileName(), q->allSelectors()); -

306 -

307 if (!ret.isEmpty()) -

308 return ret; -

309 return filePath; -

310 } -

311 -

312 /*! -

313 Returns the list of extra selectors which have been added programmatically to this instance. -

314 */ -

315 QStringList QFileSelector::extraSelectors() const -

316 { -

317 Q_D(const QFileSelector); -

318 return d->extras; -

319 } -

320 -

321 /*! -

322 Sets the \a list of extra selectors which have been added programmatically to this instance. -

323 -

324 These selectors have priority over any which have been automatically picked up. -

325 */ -

326 void QFileSelector::setExtraSelectors(const QStringList &list) -

327 { -

328 Q_D(QFileSelector); -

329 d->extras = list; -

330 } -

331 -

332 /*! -

333 Returns the complete, ordered list of selectors used by this instance -

334 */ -

335 QStringList QFileSelector::allSelectors() const -

336 { -

337 Q_D(const QFileSelector); -

338 QMutexLocker locker(&sharedDataMutex); -

339 QFileSelectorPrivate::updateSelectors(); -

340 return d->extras + sharedData->staticSelectors; -

341 } -

342 -

343 void QFileSelectorPrivate::updateSelectors() -

344 { -

345 if (!sharedData->staticSelectors.isEmpty()) -

346 return; //Already loaded -

347 -

348 QLatin1Char pathSep(','); -

349 QStringList envSelectors = QString::fromLatin1(qgetenv("QT_FILE_SELECTORS")) -

350 .split(pathSep, QString::SkipEmptyParts); -

351 if (envSelectors.count()) -

352 sharedData->staticSelectors << envSelectors; -

353 -

354 if (!qEnvironmentVariableIsEmpty(env_override)) -

355 return; -

356 -

357 sharedData->staticSelectors << sharedData->preloadedStatics; //Potential for static selectors from other modules -

358 -

359 // TODO: Update on locale changed? -

360 sharedData->staticSelectors << QLocale().name(); -

361 -

362 sharedData->staticSelectors << platformSelectors(); -

363 } -

364 -

365 QStringList QFileSelectorPrivate::platformSelectors() -

366 { -

367 // similar, but not identical to QSysInfo::osType -

368 QStringList ret; -

369 #if defined(Q_OS_WIN) -

370 // can't fall back to QSysInfo because we need both "winphone" and "winrt" for the Windows Phone case -

371 ret << QStringLiteral("windows"); -

372 ret << QSysInfo::kernelType(); // "wince" and "winnt" -

373 # if defined(Q_OS_WINRT) -

374 ret << QStringLiteral("winrt"); -

375 # if defined(Q_OS_WINPHONE) -

376 ret << QStringLiteral("winphone"); -

377 # endif -

378 # endif -

379 #elif defined(Q_OS_UNIX) -

380 ret << QStringLiteral("unix"); -

381 # if !defined(Q_OS_ANDROID) && !defined(Q_OS_BLACKBERRY) -

382 // we don't want "linux" for Android -

383 ret << QSysInfo::kernelType(); -

384 # ifdef Q_OS_MAC -

385 ret << QStringLiteral("mac"); // compatibility, since kernelType() is "darwin" -

386 # endif -

387 # endif -

388 QString productName = QSysInfo::productType(); -

389 # ifdef Q_OS_MACOS -

390 if (productName != QStringLiteralQLatin1String("osx")) -

391 ret << QStringLiteral("osx"); // compatibility -

392 # endif -

393

if (productName != QLatin1String("unknown"))

productName !=...ing("unknown")	Description
TRUE	evaluated 3 times by 1 test Evaluated by: tst_QFileSelector
FALSE	never evaluated

0-3

394

ret << productName; // "opensuse", "fedora", "macos", "ios", "android"

executed 3 times by 1 test: ret << productName;

Executed by:

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395 #endif -

396

return ret;

executed 3 times by 1 test: return ret;

Executed by:

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397 } -

398 -

399 void QFileSelectorPrivate::addStatics(const QStringList &statics) -

400 { -

401 QMutexLocker locker(&sharedDataMutex); -

402 sharedData->preloadedStatics << statics; -

403 sharedData->staticSelectors.clear(); -

404

}

executed 1 time by 1 test: end of block

Executed by:

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405 -

406 QT_END_NAMESPACE -

407 -

408 #include "moc_qfileselector.cpp" -

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