---
phase: 06-integration-and-hardening
plan: 02
subsystem: native-addon
tags: [gdi, leak-testing, windows-api, getguiresources, dwm]

requires:
  - phase: 06-01
    provides: DWM capture integration with captureWindowBest and window-utils
provides:
  - getGdiHandleCount() native addon export calling GetGuiResources
  - TypeScript wrapper for getGdiHandleCount
  - GDI handle leak validation test script (120 captures, drift +/- 5)
affects: []

tech-stack:
  added: []
  patterns: [GetGuiResources for GDI leak detection]

key-files:
  created: [tests/gdi-leak-test.ts]
  modified: [native/src/addon.cpp, src/capture/targets/dwm-capture.ts]

key-decisions:
  - "Used GetGuiResources(GetCurrentProcess(), GR_GDIOBJECTS) for GDI handle counting -- read-only, no additional includes or linker flags needed"

patterns-established:
  - "Leak test pattern: baseline -> N captures -> drift check against threshold"

requirements-completed: [DWM-12]

duration: 2min
completed: 2026-04-13
---

# Phase 6 Plan 2: GDI Handle Leak Validation Summary

**Native addon getGdiHandleCount() export via GetGuiResources API with 120-capture leak test validating drift within +/- 5**

## Performance

- **Duration:** 2 min
- **Started:** 2026-04-13T07:33:25Z
- **Completed:** 2026-04-13T07:35:14Z
- **Tasks:** 2
- **Files modified:** 3

## Accomplishments
- Added getGdiHandleCount() to native addon calling Windows GetGuiResources API
- Exposed TypeScript wrapper returning -1 when addon unavailable
- Created comprehensive leak test script running 120 captures with periodic drift reporting

## Task Commits

Each task was committed atomically:

1. **Task 1: Add getGdiHandleCount() to native addon and TypeScript wrapper** - `5adc259` (feat)
2. **Task 2: Create GDI handle leak test script** - `b4b5ab7` (test)

## Files Created/Modified
- `native/src/addon.cpp` - Added GetGdiHandleCount function calling GetGuiResources, exported in Init
- `src/capture/targets/dwm-capture.ts` - Added getGdiHandleCount to NativeAddon interface and exported wrapper
- `tests/gdi-leak-test.ts` - Standalone leak test: 120 DWM captures, GDI drift validation within +/- 5

## Decisions Made
- Used GetGuiResources(GetCurrentProcess(), GR_GDIOBJECTS) -- no new includes or linker flags needed since windows.h and user32.lib are already available
- Returns -1 from TypeScript wrapper when addon not loaded (consistent with existing pattern of graceful degradation)

## Deviations from Plan

None - plan executed exactly as written.

## Issues Encountered
None

## User Setup Required
None - no external service configuration required.

## Next Phase Readiness
- GDI leak validation infrastructure in place
- Test can be run manually on Windows with built addon: `npx tsx tests/gdi-leak-test.ts`
- Ready for any subsequent hardening or integration work

## Self-Check: PASSED

- All 3 files exist (addon.cpp, dwm-capture.ts, gdi-leak-test.ts)
- Both commits found (5adc259, b4b5ab7)
- Content patterns verified (GetGdiHandleCount, getGdiHandleCount, CAPTURE_COUNT=120, drift threshold)

---
*Phase: 06-integration-and-hardening*
*Completed: 2026-04-13*