Add the SDWebImageContextStoreCacheType context option to specify target cache type when the image is downloaded by manager and will store to cache

[dreampiggy]

This replace the previous SDWebImageCacheMemoryOnly option, which is not so accurate and lack of detail control for cache behavior.

New Pull Request Checklist

• I have read and understood the CONTRIBUTING guide

• I have read the Documentation

• I have searched for a similar pull request in the project and found none

• I have updated this branch with the latest master to avoid conflicts (via merge from master or rebase)

• I have added the required tests to prove the fix/feature I am adding

• I have updated the documentation (if necessary)

• I have run the tests and they pass

• I have run the lint and it passes (pod lib lint)

This merge request fixes / reffers to the following issues: ...

Pull Request Description

Reason

Current SDWebImageCacheMemoryOnly options is good for some big images, or tempory image which is no need to store in the disk cache.

However, there are still some people including me, hope to totally disable cache storage for some of images. For example, when query the image from Photos Library plugin, we don't want to store the image into disk cache or memory cache at all. Because the cost to load the image again is quite cheap.

We already done something like Custom Cache and allow user to sepcify 4 type of store cache behavior : store disk only, store memory only, store memory and disk, do not store. So I think now we can adopt a better solution for our user who need the detailed control for cache behavior.

Design

We should treat this cache type control as individual image request level. So the best choice is using SDWebImageContextOption. We just pass the target cache type from the user and use that to decide cache storage.

Implementation

/**
 A SDImageCacheType raw value which specify the cache type when the image has just been downloaded and will be stored to the cache. Specify `SDImageCacheTypeNone` to disable cache storage; `SDImageCacheTypeDisk` to store in disk cache only; `SDImageCacheTypeMemory` to store in memory only. And `SDImageCacheTypeAll` to store in both memory cache and disk cache.
 If not provide or the value is invalid, we will use `SDImageCacheTypeAll`. (NSNumber)
 */
FOUNDATION_EXPORT SDWebImageContextOption _Nonnull const SDWebImageContextStoreCacheType;

[codecov-io]

Codecov Report

Merging #2360 into 5.x will decrease coverage by 0.11%.
The diff coverage is 50%.

@@            Coverage Diff            @@
##              5.x   #2360      +/-   ##
=========================================
- Coverage   69.22%   69.1%   -0.12%     
=========================================
  Files          48      48              
  Lines        6690    6690              
=========================================
- Hits         4631    4623       -8     
- Misses       2059    2067       +8

Flag	Coverage Δ
#iOS	70.07% <50%> (-0.17%)	⬇️
#macOS	68.03% <50%> (+0.08%)	⬆️

Impacted Files	Coverage Δ
SDWebImage/SDWebImageDefine.m	32.87% <ø> (ø)	⬆️
SDWebImage/SDWebImageManager.m	82.25% <50%> (ø)	⬆️
SDWebImage/SDWebImageDownloaderOperation.m	85.32% <0%> (-3.08%)	⬇️
SDWebImage/SDWebImageDownloader.m	81.5% <0%> (+0.34%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 997bf8f...e5bee68. Read the comment docs.

[dreampiggy]

Current break change (Need change code)

SDWebImageDefine.h

• SDWebImageCacheMemoryOnly REMOVED. Use SDWebImageContextStoreCacheType option with SDImageCacheTypeMemory instead.

[mythodeia]

👍

[bpoplauschi]

👍