Respond to CR.

// FREEBIE
This commit is contained in:
Matthew Chen 2017-10-31 11:56:13 -04:00
parent cfb2a720d7
commit 487bd06755
2 changed files with 112 additions and 103 deletions

View File

@ -147,6 +147,9 @@ class GifPickerViewController: OWSViewController, UISearchBarDelegate, UICollect
private func createViews() {
view.backgroundColor = UIColor.white
// Block UIKit from adjust insets of collection view which screws up
// min/max scroll positions.
self.automaticallyAdjustsScrollViewInsets = false
// Search

View File

@ -23,14 +23,21 @@ class GiphyAssetSegment {
public let index: UInt
public let segmentStart: UInt
public let segmentLength: UInt
// The amount of the segment that is overlap.
// The overlap lies in the _first_ n bytes of the segment data.
public let redundantLength: UInt
// This state should only be accessed on the main thread.
public var state: GiphyAssetSegmentState = .waiting {
didSet {
AssertIsOnMainThread()
}
}
private var datas = [Data]()
// This state is accessed off the main thread.
//
// * During downloads it will be accessed on the task delegate queue.
// * After downloads it will be accessed on a worker queue.
private var segmentData = NSMutableData()
init(index: UInt,
segmentStart: UInt,
@ -43,11 +50,7 @@ class GiphyAssetSegment {
}
public func totalDataSize() -> UInt {
var result: UInt = 0
for data in datas {
result += UInt(data.count)
}
return result
return UInt(segmentData.length)
}
public func append(data: Data) {
@ -56,37 +59,31 @@ class GiphyAssetSegment {
return
}
datas.append(data)
segmentData.append(data)
}
public func mergeData(assetData: NSMutableData) {
public func mergeData(assetData: NSMutableData) -> Bool {
guard state == .complete else {
owsFail("\(TAG) merging data in invalid state: \(state)")
return
return false
}
guard UInt(segmentData.length) == segmentLength else {
owsFail("\(TAG) segment data length: \(segmentData.length) doesn't match expected length: \(segmentLength)")
return false
}
// In some cases the last two segments will overlap.
// In that case, we only want to append the non-overlapping
// tail of the last segment.
var bytesToIgnore = Int(redundantLength)
var totalDataBytes: UInt = 0
for data in datas {
totalDataBytes += UInt(data.count)
if data.count <= bytesToIgnore {
bytesToIgnore -= data.count
} else if bytesToIgnore > 0 {
let range = NSMakeRange(bytesToIgnore, data.count - bytesToIgnore)
let subdata = (data as NSData).subdata(with: range)
assetData.append(subdata)
bytesToIgnore = 0
} else {
assetData.append(data)
}
}
guard totalDataBytes == segmentLength else {
owsFail("\(TAG) segment data length: \(totalDataBytes) doesn't match expected length: \(segmentLength)")
return
// tail of the segment data.
let bytesToIgnore = Int(redundantLength)
if bytesToIgnore > 0 {
let range = NSMakeRange(bytesToIgnore, segmentData.length - bytesToIgnore)
let subdata = (segmentData as NSData).subdata(with: range)
assetData.append(subdata)
} else {
assetData.append(segmentData as Data)
}
return true
}
}
@ -122,6 +119,7 @@ enum GiphyAssetRequestState: UInt {
// This property is an internal implementation detail of the download process.
var assetFilePath: String?
// This state should only be accessed on the main thread.
private var segments = [GiphyAssetSegment]()
public var state: GiphyAssetRequestState = .waiting
public var contentLength: Int = 0 {
@ -260,7 +258,10 @@ enum GiphyAssetRequestState: UInt {
owsFail("\(TAG) could not merge empty segment.")
return nil
}
segment.mergeData(assetData: assetData)
guard segment.mergeData(assetData: assetData) else {
owsFail("\(TAG) failed to merge segment data.")
return nil
}
}
guard assetData.length == contentLength else {
@ -496,7 +497,13 @@ extension URLSessionTask {
success:success,
failure:failure)
assetRequestQueue.append(assetRequest)
processRequestQueue()
// Process the queue (which may start this request)
// asynchronously so that the caller has time to store
// a reference to the asset request returned by this
// method before its success/failure handler is called.
DispatchQueue.main.async {
self.processRequestQueue()
}
return assetRequest
}
@ -575,83 +582,82 @@ extension URLSessionTask {
processRequestQueue()
}
// Start a request if necessary, complete asset requests if possible.
// * Start a segment request or content length request if possible.
// * Complete/cancel asset requests if possible.
//
private func processRequestQueue() {
AssertIsOnMainThread()
DispatchQueue.main.async {
guard let assetRequest = self.popNextAssetRequest() else {
return
}
guard !assetRequest.wasCancelled else {
// Discard the cancelled asset request and try again.
self.removeAssetRequestFromQueue(assetRequest: assetRequest)
return
}
guard UIApplication.shared.applicationState == .active else {
// If app is not active, fail the asset request.
assetRequest.state = .failed
self.assetRequestDidFail(assetRequest:assetRequest)
self.processRequestQueue()
return
}
if let asset = self.assetMap.get(key:assetRequest.rendition.url) {
// Deferred cache hit, avoids re-downloading assets that were
// downloaded while this request was queued.
assetRequest.state = .complete
self.assetRequestDidSucceed(assetRequest : assetRequest, asset: asset)
return
}
guard let downloadSession = self.giphyDownloadSession() else {
owsFail("\(self.TAG) Couldn't create session manager.")
assetRequest.state = .failed
self.assetRequestDidFail(assetRequest:assetRequest)
return
}
if assetRequest.state == .waiting {
// If asset request hasn't yet determined the resource size,
// try to do so now.
assetRequest.state = .requestingSize
var request = URLRequest(url: assetRequest.rendition.url as URL)
request.httpMethod = "HEAD"
let task = downloadSession.dataTask(with:request, completionHandler: { [weak self] data, response, error -> Void in
if let data = data {
if data.count > 0 {
owsFail("\(self?.TAG) HEAD request has unexpected body: \(data.count).")
}
}
self?.handleAssetSizeResponse(assetRequest:assetRequest, response:response, error:error)
})
task.resume()
} else {
// Start a download task.
guard let assetSegment = assetRequest.firstWaitingSegment() else {
owsFail("\(self.TAG) queued asset request does not have a waiting segment.")
return
}
assetSegment.state = .downloading
var request = URLRequest(url: assetRequest.rendition.url as URL)
let rangeHeaderValue = "bytes=\(assetSegment.segmentStart)-\(assetSegment.segmentStart + assetSegment.segmentLength - 1)"
request.addValue(rangeHeaderValue, forHTTPHeaderField: "Range")
let task = downloadSession.dataTask(with:request)
task.assetRequest = assetRequest
task.assetSegment = assetSegment
task.resume()
}
// Recurse; we may be able to start multiple downloads.
self.processRequestQueue()
guard let assetRequest = self.popNextAssetRequest() else {
return
}
guard !assetRequest.wasCancelled else {
// Discard the cancelled asset request and try again.
self.removeAssetRequestFromQueue(assetRequest: assetRequest)
return
}
guard UIApplication.shared.applicationState == .active else {
// If app is not active, fail the asset request.
assetRequest.state = .failed
self.assetRequestDidFail(assetRequest:assetRequest)
self.processRequestQueue()
return
}
if let asset = self.assetMap.get(key:assetRequest.rendition.url) {
// Deferred cache hit, avoids re-downloading assets that were
// downloaded while this request was queued.
assetRequest.state = .complete
self.assetRequestDidSucceed(assetRequest : assetRequest, asset: asset)
return
}
guard let downloadSession = self.giphyDownloadSession() else {
owsFail("\(self.TAG) Couldn't create session manager.")
assetRequest.state = .failed
self.assetRequestDidFail(assetRequest:assetRequest)
return
}
if assetRequest.state == .waiting {
// If asset request hasn't yet determined the resource size,
// try to do so now.
assetRequest.state = .requestingSize
var request = URLRequest(url: assetRequest.rendition.url as URL)
request.httpMethod = "HEAD"
let task = downloadSession.dataTask(with:request, completionHandler: { [weak self] data, response, error -> Void in
if let data = data {
if data.count > 0 {
owsFail("\(self?.TAG) HEAD request has unexpected body: \(data.count).")
}
}
self?.handleAssetSizeResponse(assetRequest:assetRequest, response:response, error:error)
})
task.resume()
} else {
// Start a download task.
guard let assetSegment = assetRequest.firstWaitingSegment() else {
owsFail("\(self.TAG) queued asset request does not have a waiting segment.")
return
}
assetSegment.state = .downloading
var request = URLRequest(url: assetRequest.rendition.url as URL)
let rangeHeaderValue = "bytes=\(assetSegment.segmentStart)-\(assetSegment.segmentStart + assetSegment.segmentLength - 1)"
request.addValue(rangeHeaderValue, forHTTPHeaderField: "Range")
let task = downloadSession.dataTask(with:request)
task.assetRequest = assetRequest
task.assetSegment = assetSegment
task.resume()
}
// Recurse; we may be able to start multiple downloads.
self.processRequestQueue()
}
private func handleAssetSizeResponse(assetRequest: GiphyAssetRequest, response: URLResponse?, error: Error?) {