---
phase: 08-pagination-quality-cache-performance
plan: 03
type: execute
wave: 2
depends_on:
- 08-01
- 08-02
files_modified:
- Sources/RDReaderView/EPUBTextRendering/RDEPUBTextPerformanceSampler.swift
- Sources/RDReaderView/EPUBTextRendering/RDEPUBTextBookBuilder.swift
autonomous: true
requirements:
- QUAL-01
- QUAL-04
must_haves:
truths:
- "Builder records per-chapter render time and paginate time"
- "Builder records total build time"
- "Builder records cache hit/miss per chapter"
- "Performance samples are accessible via lastBuildPerformanceSamples"
- "Cache integration: builder accepts optional cache parameter and skips build on hit"
- "Cache miss triggers full build and stores result"
- "Console logs show [PERF] summary with timing data"
artifacts:
- path: "Sources/RDReaderView/EPUBTextRendering/RDEPUBTextPerformanceSampler.swift"
provides: "RDEPUBTextPerformanceSample struct and RDEPUBTextPerformanceSampler class"
contains: "struct RDEPUBTextPerformanceSample"
- path: "Sources/RDReaderView/EPUBTextRendering/RDEPUBTextBookBuilder.swift"
provides: "Cache integration and performance instrumentation in build()"
contains: "lastBuildPerformanceSamples"
key_links:
- from: "RDEPUBTextBookBuilder.swift"
to: "RDEPUBTextBookCache.swift"
via: "cache.load(key:) / cache.save(_:key:)"
pattern: "cache\\.load\\|cache\\.save"
- from: "RDEPUBTextBookBuilder.swift"
to: "RDEPUBTextPerformanceSampler.swift"
via: "sampler.record(sample)"
pattern: "sampler\\.record"
---
Create performance sampling infrastructure and integrate cache + performance instrumentation into RDEPUBTextBookBuilder.build(). This adds timing measurements for render/paginate/build operations and wires the cache from Plan 01 so that repeated builds with the same parameters skip the full pipeline.
Purpose: QUAL-04 requires stable diagnostic/sampling data to ensure no degradation. QUAL-01 requires cache integration to avoid redundant pagination. This plan brings both into the builder.
Output: New RDEPUBTextPerformanceSampler.swift; modified RDEPUBTextBookBuilder.swift with cache integration and timing instrumentation.
@$HOME/.claude/get-shit-done/workflows/execute-plan.md
@$HOME/.claude/get-shit-done/templates/summary.md
@.planning/PROJECT.md
@.planning/ROADMAP.md
@.planning/STATE.md
@.planning/phases/08-pagination-quality-cache-performance/08-CONTEXT.md
@.planning/phases/08-pagination-quality-cache-performance/08-RESEARCH.md
@.planning/phases/08-pagination-quality-cache-performance/08-PATTERNS.md
@.planning/phases/08-pagination-quality-cache-performance/08-01-SUMMARY.md
@.planning/phases/08-pagination-quality-cache-performance/08-02-SUMMARY.md
@Sources/RDReaderView/EPUBTextRendering/RDEPUBTextBookBuilder.swift
@Sources/RDReaderView/EPUBTextRendering/RDEPUBTextBookCache.swift
@Sources/RDReaderView/EPUBTextRendering/RDEPUBTextPerformanceSampler.swift
@Sources/RDReaderView/EPUBTextRendering/RDEPUBTextRenderer.swift
```swift
public init(renderer: RDEPUBTextRenderer) {
self.renderer = renderer
}
public convenience init() {
self.init(renderer: RDEPUBDTCoreTextRenderer())
}
```
```swift
public private(set) var lastBuildResourceDiagnostics: [RDEPUBTextResourceReferenceDiagnostic] = []
public private(set) var lastBuildPaginationDiagnostics: [RDEPUBTextChapterPaginationDiagnostic] = []
```
```swift
public func build(
parser: RDEPUBParser,
publication: RDEPUBPublication,
pageSize: CGSize,
style: RDEPUBTextRenderStyle
) throws -> RDEPUBTextBook
```
```swift
public final class RDEPUBTextBookCache {
public init(subdirectory: String = "RDEPUBTextBookCache")
public func cacheKey(bookID: String, fontSize: CGFloat, lineHeightMultiple: CGFloat, contentInsets: UIEdgeInsets, pageSize: CGSize) -> String
public func load(key: String) -> RDEPUBTextBook?
public func save(_ book: RDEPUBTextBook, key: String)
public func invalidateAll()
public var schemaVersion: Int
}
```
```swift
let start = CFAbsoluteTimeGetCurrent()
// ... operation ...
let duration = CFAbsoluteTimeGetCurrent() - start
```
```swift
public struct RDEPUBTextResourceReferenceDiagnostic: Equatable {
public var kind: RDEPUBTextResourceReferenceKind
public var chapterHref: String
// ...
public init(kind: ..., chapterHref: ..., ...) { ... }
}
```
```swift
extension NSAttributedString {
func rd_paginatedFrames(
size: CGSize,
fragmentOffsets: [String: Int] = [:],
config: RDEPUBTextLayoutConfig = .default
) -> [RDEPUBTextLayoutFrame]
}
```
Task 1: Create RDEPUBTextPerformanceSampler with timing sample struct and recording API
Sources/RDReaderView/EPUBTextRendering/RDEPUBTextPerformanceSampler.swift
Sources/RDReaderView/EPUBTextRendering/RDEPUBTextRenderer.swift
Sources/RDReaderView/EPUBTextRendering/RDEPUBTextBookBuilder.swift
Create a new file `Sources/RDReaderView/EPUBTextRendering/RDEPUBTextPerformanceSampler.swift`.
**RDEPUBTextPerformanceSample struct** (per QUAL-04, D-04):
```swift
public struct RDEPUBTextPerformanceSample: Equatable {
public var chapterHref: String
public var renderDuration: TimeInterval // DTCoreText render time
public var paginateDuration: TimeInterval // CoreText pagination time
public var pageCount: Int
public var attributedStringLength: Int
public var cacheHit: Bool
public init(
chapterHref: String,
renderDuration: TimeInterval,
paginateDuration: TimeInterval,
pageCount: Int,
attributedStringLength: Int,
cacheHit: Bool
) { ... }
}
```
Follow the exact pattern from `RDEPUBTextResourceReferenceDiagnostic` at RDEPUBTextRenderer.swift lines 90-113: public struct, Equatable, explicit public init with all properties.
**RDEPUBTextPerformanceSampler class**:
```swift
public final class RDEPUBTextPerformanceSampler {
public private(set) var samples: [RDEPUBTextPerformanceSample] = []
public private(set) var totalBuildDuration: TimeInterval = 0
public init() {}
public func record(_ sample: RDEPUBTextPerformanceSample) {
samples.append(sample)
print("[PERF] \(sample.chapterHref): render=\(formatMS(sample.renderDuration)) paginate=\(formatMS(sample.paginateDuration)) pages=\(sample.pageCount) cache=\(sample.cacheHit ? "HIT" : "MISS")")
}
public func summary() -> String {
let totalRender = samples.reduce(0) { $0 + $1.renderDuration }
let totalPaginate = samples.reduce(0) { $0 + $1.paginateDuration }
let hitCount = samples.filter(\.cacheHit).count
return "[PERF] chapters=\(samples.count) render=\(formatMS(totalRender)) paginate=\(formatMS(totalPaginate)) total=\(formatMS(totalBuildDuration)) cacheHits=\(hitCount)/\(samples.count)"
}
public func reset() {
samples.removeAll()
totalBuildDuration = 0
}
private func formatMS(_ duration: TimeInterval) -> String {
String(format: "%.0fms", duration * 1000)
}
}
```
**Console output pattern** (follows existing `[EPUB]` style in the codebase):
- Each `record()` call prints a per-chapter `[PERF]` line
- `summary()` returns a formatted string (caller prints it)
- Use milliseconds (multiply TimeInterval by 1000) for human-readable output
xcodebuild build -scheme ReadViewDemo -destination 'platform=iOS Simulator,name=iPhone 17' 2>&1 | tail -5
- File `Sources/RDReaderView/EPUBTextRendering/RDEPUBTextPerformanceSampler.swift` exists
- `RDEPUBTextPerformanceSample` is a public struct with Equatable conformance
- Properties: `chapterHref`, `renderDuration`, `paginateDuration`, `pageCount`, `attributedStringLength`, `cacheHit`
- `RDEPUBTextPerformanceSampler` is a public final class
- `record(_:)` method appends sample and prints `[PERF]` line
- `summary()` returns formatted string with totals and cache hit rate
- `reset()` clears samples and totalBuildDuration
- `totalBuildDuration` is a public property
- Build succeeds
RDEPUBTextPerformanceSampler.swift contains performance sample struct and sampler class with record/summary/reset API and [PERF] console logging. Build succeeds.
Task 2: Integrate cache and performance sampling into RDEPUBTextBookBuilder.build()
Sources/RDReaderView/EPUBTextRendering/RDEPUBTextBookBuilder.swift
Sources/RDReaderView/EPUBTextRendering/RDEPUBTextBookBuilder.swift
Sources/RDReaderView/EPUBTextRendering/RDEPUBTextBookCache.swift
Sources/RDReaderView/EPUBTextRendering/RDEPUBTextPerformanceSampler.swift
Sources/RDReaderView/EPUBTextRendering/RDEPUBTextRenderer.swift
Sources/RDReaderView/EPUBUI/RDEPUBReaderController.swift
Modify `RDEPUBTextBookBuilder.swift` to integrate the cache (from Plan 01) and performance sampling (Task 1).
**Step 1: Add new stored properties** (per D-01, D-04)
After the existing `lastBuildPaginationDiagnostics` property (line 99), add:
```swift
public private(set) var lastBuildPerformanceSamples: [RDEPUBTextPerformanceSample] = []
public private(set) var lastBuildCacheStats: (hits: Int, misses: Int) = (0, 0)
```
**Step 2: Add cache and sampler to init** (per D-01)
Update the initializer to accept optional cache:
```swift
private let cache: RDEPUBTextBookCache?
private let sampler: RDEPUBTextPerformanceSampler
public init(renderer: RDEPUBTextRenderer, cache: RDEPUBTextBookCache? = nil) {
self.renderer = renderer
self.cache = cache
self.sampler = RDEPUBTextPerformanceSampler()
}
public convenience init() {
self.init(renderer: RDEPUBDTCoreTextRenderer())
}
```
The `cache` parameter defaults to nil for backward compatibility. The sampler is always created (lightweight, no cost until samples recorded).
**Step 3: Add cache key helper**
Add a private helper method to generate the cache key from build parameters:
```swift
private func makeCacheKey(
bookID: String,
pageSize: CGSize,
style: RDEPUBTextRenderStyle
) -> String? {
guard let cache else { return nil }
return cache.cacheKey(
bookID: bookID,
fontSize: style.font.pointSize,
lineHeightMultiple: style.lineSpacing,
contentInsets: .zero, // or derive from pageSize insets if available
pageSize: pageSize
)
}
```
Note: The `bookID` needs to come from the publication. Use `publication.metadata.identifier ?? publication.metadata.title ?? "unknown"` as the bookID. If no identifier is available, return nil to skip caching.
**Step 4: Instrument the build() method** (per QUAL-04, QUAL-01)
At the start of `build()`, after the existing `lastBuildResourceDiagnostics = []` / `lastBuildPaginationDiagnostics = []` lines:
1. **Reset sampler**: `sampler.reset()`, `lastBuildCacheStats = (0, 0)`
2. **Start build timer**: `let buildStart = CFAbsoluteTimeGetCurrent()`
3. **Cache lookup**: If cache is available, generate key and try `cache.load(key:)`. If hit, set `lastBuildCacheStats.hits += 1`, print `[Cache] HIT`, and return the cached book immediately.
4. **Cache miss**: If cache miss, proceed with existing build loop.
Inside the for loop, around each chapter's render + paginate:
1. **Render timing**: Wrap `renderer.renderChapter(request:)` (line 158) with `CFAbsoluteTimeGetCurrent()` before and after
2. **Paginate timing**: Wrap `content.rd_paginatedFrames(size:)` (line 196) with `CFAbsoluteTimeGetCurrent()` before and after
3. **Record sample**: After getting layoutFrames, record:
```swift
sampler.record(RDEPUBTextPerformanceSample(
chapterHref: item.href,
renderDuration: renderDuration,
paginateDuration: paginateDuration,
pageCount: effectiveFrames.count,
attributedStringLength: content.length,
cacheHit: false
))
```
4. **Miss counter**: `lastBuildCacheStats.misses += 1`
After the loop, before returning:
1. **Set total build duration**: `sampler.totalBuildDuration = CFAbsoluteTimeGetCurrent() - buildStart`
2. **Save to cache**: If cache available and key was generated, `cache.save(book, key: cacheKey)`
3. **Print summary**: `print(sampler.summary())`
4. **Store samples**: `lastBuildPerformanceSamples = sampler.samples`
**Step 5: Update build() method signature** — keep the existing signature unchanged. The cache is accessed via the stored property, not a method parameter.
**Important implementation notes**:
- All timing uses `CFAbsoluteTimeGetCurrent()` (no external deps, per D-04)
- Timing happens on the same queue as the build (DispatchQueue.global(qos: .userInitiated)), not dispatched to main
- The `publication.metadata.identifier` or equivalent needs to be accessible — check the `RDEPUBPublication` type for an identifier field
- If publication has no identifier, skip cache (return nil from makeCacheKey)
xcodebuild build -scheme ReadViewDemo -destination 'platform=iOS Simulator,name=iPhone 17' 2>&1 | tail -5
- `RDEPUBTextBookBuilder` has `lastBuildPerformanceSamples: [RDEPUBTextPerformanceSample]` property
- `RDEPUBTextBookBuilder` has `lastBuildCacheStats: (hits: Int, misses: Int)` property
- `RDEPUBTextBookBuilder` init accepts optional `cache: RDEPUBTextBookCache?` parameter (defaults to nil)
- `build()` method contains `CFAbsoluteTimeGetCurrent()` timing calls for render and paginate
- `build()` method calls `cache.load(key:)` before the build loop when cache is available
- `build()` method calls `cache.save(_:key:)` after the build loop when cache is available
- `build()` method calls `sampler.record()` for each chapter with timing data
- `build()` method prints `sampler.summary()` at the end
- Existing `convenience init()` still works (cache defaults to nil)
- Build succeeds with no regressions
RDEPUBTextBookBuilder.build() is instrumented with per-chapter render/paginate timing, cache hit/miss logging, and performance sample recording. Cache integration skips build on hit and stores result on miss. Build succeeds.
## Trust Boundaries
| Boundary | Description |
|----------|-------------|
| builder → cache | Builder writes to cache after successful build; corrupted cache could return invalid RDEPUBTextBook on next load |
## STRIDE Threat Register
| Threat ID | Category | Component | Disposition | Mitigation |
|-----------|----------|-----------|-------------|------------|
| T-08-04 | Tampering | Cache integration in builder | accept | Cache is optional (nil default); NSKeyedArchiver deserialization fails safely returning nil |
| T-08-SC | Tampering | npm/pip/cargo installs | mitigate | No external packages installed in this phase |
- `xcodebuild build -scheme ReadViewDemo` succeeds
- Builder init accepts optional cache parameter
- build() method has CFAbsoluteTimeGetCurrent timing instrumentation
- Cache load/save calls are present in build() flow
- Performance samples accessible via lastBuildPerformanceSamples
- Console shows [PERF] summary and [Cache] HIT/MISS logs
- Per-chapter render and paginate durations are recorded
- Total build time is captured
- Cache hit skips the entire build loop
- Cache miss runs full build and stores result
- Performance summary printed to console after each build
- No functional regression: book opens, paginates, and displays correctly