func describeAllSegments()

in Sources/TSFCASFileTree/FileTreeImport.swift [771:815]
37 lines of code
8 McCabe index (conditional complexity)

    func describeAllSegments(of file: FileSegmenter, _ ctx: Context) throws -> [SegmentDescriptor] {
        var descriptions: [SegmentDescriptor] = []

        for segmentNumber in (0...Int.max) {
            let (data, isEOF): (LLBFastData, Bool)
            do {
                guard let value = try file.fetchSegment(segmentNumber: segmentNumber) else {
                    // File EOF'ed prematurely.
                    if self.options.relaxConsistencyChecks {
                        return descriptions
                    } else {
                        throw FileSegmenter.Error.resourceChanged(reason: "Can't read")
                    }
                }
                (data, isEOF) = value
            } catch FileSegmenter.Error.resourceChanged(let reason) {
                // Translate this resource consistency error,
                // will throw all the rest as is.
                throw ImportError.modifiedFile(file.path, reason: reason)
            }

            var useCompression: Bool
            if case .compressed = options.wireFormat, file.size > 1024, !file.path.looksLikeCompressed, options.compressBufferAllocator != nil {
                useCompression = true
            } else {
                useCompression = false
            }

            let segment: AnnotatedSegment
            if useCompression, let compressedSegment = try? data.compressed(allocator: options.compressBufferAllocator!) {

                segment = AnnotatedSegment(isCompressed: true, uncompressedSize: data.count, data: compressedSegment)
            } else {
                useCompression = false
                segment = AnnotatedSegment(isCompressed: false, uncompressedSize: data.count, data: data)
            }

            descriptions.append(.init(of: segment, id: _db.identify(refs: [], data: segment.data.toByteBuffer(), ctx)))
            if isEOF {
                break
            }
        }
        assert(descriptions.reduce(0, { acc, d in acc + d.uncompressedSize }) == file.size)
        return descriptions
    }