yuncms /
framework
| Conditions | 16 |
| Paths | 31 |
| Total Lines | 91 |
| Lines | 0 |
| Ratio | 0 % |
| Changes | 1 | ||
| Bugs | 0 | Features | 0 |
Small methods make your code easier to understand, in particular if combined with a good name. Besides, if your method is small, finding a good name is usually much easier.
For example, if you find yourself adding comments to a method's body, this is usually a good sign to extract the commented part to a new method, and use the comment as a starting point when coming up with a good name for this new method.
Commonly applied refactorings include:
If many parameters/temporary variables are present:
Complex classes like load-image-exif.js ➔ ... ➔ loadImage.parseExifData often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
| 1 | /* |
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| 217 | loadImage.parseExifData = function (dataView, offset, length, data, options) { |
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| 218 | if (options.disableExif) { |
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| 219 | return |
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| 220 | } |
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| 221 | var tiffOffset = offset + 10 |
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| 222 | var littleEndian |
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| 223 | var dirOffset |
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| 224 | var thumbnailData |
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| 225 | // Check for the ASCII code for "Exif" (0x45786966): |
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| 226 | if (dataView.getUint32(offset + 4) !== 0x45786966) { |
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| 227 | // No Exif data, might be XMP data instead |
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| 228 | return |
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| 229 | } |
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| 230 | if (tiffOffset + 8 > dataView.byteLength) { |
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| 231 | console.log('Invalid Exif data: Invalid segment size.') |
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| 232 | return |
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| 233 | } |
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| 234 | // Check for the two null bytes: |
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| 235 | if (dataView.getUint16(offset + 8) !== 0x0000) { |
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| 236 | console.log('Invalid Exif data: Missing byte alignment offset.') |
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| 237 | return |
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| 238 | } |
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| 239 | // Check the byte alignment: |
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| 240 | switch (dataView.getUint16(tiffOffset)) { |
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| 241 | case 0x4949: |
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| 242 | littleEndian = true |
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| 243 | break |
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| 244 | case 0x4d4d: |
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| 245 | littleEndian = false |
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| 246 | break |
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| 247 | default: |
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| 248 | console.log('Invalid Exif data: Invalid byte alignment marker.') |
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| 249 | return |
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| 250 | } |
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| 251 | // Check for the TIFF tag marker (0x002A): |
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| 252 | if (dataView.getUint16(tiffOffset + 2, littleEndian) !== 0x002a) { |
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| 253 | console.log('Invalid Exif data: Missing TIFF marker.') |
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| 254 | return |
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| 255 | } |
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| 256 | // Retrieve the directory offset bytes, usually 0x00000008 or 8 decimal: |
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| 257 | dirOffset = dataView.getUint32(tiffOffset + 4, littleEndian) |
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| 258 | // Create the exif object to store the tags: |
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| 259 | data.exif = new loadImage.ExifMap() |
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| 260 | // Parse the tags of the main image directory and retrieve the |
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| 261 | // offset to the next directory, usually the thumbnail directory: |
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| 262 | dirOffset = loadImage.parseExifTags( |
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| 263 | dataView, |
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| 264 | tiffOffset, |
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| 265 | tiffOffset + dirOffset, |
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| 266 | littleEndian, |
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| 267 | data |
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| 268 | ) |
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| 269 | if (dirOffset && !options.disableExifThumbnail) { |
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| 270 | thumbnailData = { exif: {} } |
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| 271 | dirOffset = loadImage.parseExifTags( |
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| 272 | dataView, |
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| 273 | tiffOffset, |
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| 274 | tiffOffset + dirOffset, |
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| 275 | littleEndian, |
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| 276 | thumbnailData |
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| 277 | ) |
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| 278 | // Check for JPEG Thumbnail offset: |
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| 279 | if (thumbnailData.exif[0x0201]) { |
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| 280 | data.exif.Thumbnail = loadImage.getExifThumbnail( |
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| 281 | dataView, |
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| 282 | tiffOffset + thumbnailData.exif[0x0201], |
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| 283 | thumbnailData.exif[0x0202] // Thumbnail data length |
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| 284 | ) |
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| 285 | } |
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| 286 | } |
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| 287 | // Check for Exif Sub IFD Pointer: |
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| 288 | if (data.exif[0x8769] && !options.disableExifSub) { |
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| 289 | loadImage.parseExifTags( |
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| 290 | dataView, |
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| 291 | tiffOffset, |
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| 292 | tiffOffset + data.exif[0x8769], // directory offset |
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| 293 | littleEndian, |
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| 294 | data |
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| 295 | ) |
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| 296 | } |
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| 297 | // Check for GPS Info IFD Pointer: |
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| 298 | if (data.exif[0x8825] && !options.disableExifGps) { |
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| 299 | loadImage.parseExifTags( |
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| 300 | dataView, |
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| 301 | tiffOffset, |
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| 302 | tiffOffset + data.exif[0x8825], // directory offset |
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| 303 | littleEndian, |
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| 304 | data |
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| 305 | ) |
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| 306 | } |
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| 307 | } |
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| 308 | |||
| 321 |
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