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Add mutex for CGDataProviderDirectCallbacks

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Max Radermacher 2026-05-11 17:07:50 -05:00 committed by GitHub
parent ef0dd93115
commit ada2838601
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GPG Key ID: B5690EEEBB952194
1 changed files with 16 additions and 12 deletions
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28
SignalServiceKit/Util/CGDataProvider+SSK.swift
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@ -20,10 +20,12 @@ extension FileHandle: CGDataProviderFileHandle {
extension CGDataProvider {
// Class-bound wrapper around a FileHandle
private class FileHandleWrapper {
let fileHandle: any CGDataProviderFileHandle
// It may be possible for `getBytesAtPosition` to be invoked from multiple
// threads concurrently, so add a lock to ensure mutual exclusion.
let fileHandle: TSMutex<any CGDataProviderFileHandle>
init(_ fileHandle: any CGDataProviderFileHandle) {
self.fileHandle = fileHandle
self.fileHandle = TSMutex(initialState: fileHandle)
}
}
@ -37,17 +39,19 @@ extension CGDataProvider {
return 0
}
let fileHandle = Unmanaged<FileHandleWrapper>.fromOpaque(info).takeUnretainedValue().fileHandle
do {
if offset != (try fileHandle.offset()) {
try fileHandle.seek(toOffset: UInt64(offset))
return fileHandle.withLock {
do {
if offset != (try $0.offset()) {
try $0.seek(toOffset: UInt64(offset))
}
let data = try $0.readNonOptional(upToCount: byteCount)
data.withUnsafeBytes { bytes in
buffer.copyMemory(from: bytes.baseAddress!, byteCount: bytes.count)
}
return data.count
} catch {
return 0
}
let data = try fileHandle.readNonOptional(upToCount: byteCount)
data.withUnsafeBytes { bytes in
buffer.copyMemory(from: bytes.baseAddress!, byteCount: bytes.count)
}
return data.count
} catch {
return 0
}
},
releaseInfo: { info in