analysis for temporary files

2026-03-25 09:29:48 +01:00
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+# Temporary File Cleanup Analysis
+
+## Overview
+
+Analysis of temporary file creation and cleanup patterns across the Amethyst codebase.
+The goal is to identify opportunities for more aggressive cleanup — deleting temp files
+as soon as they are no longer needed rather than deferring to cache cleanup.
+
+## Temporary File Creation Sites (Android)
+
+| Area | File | Creates | Cleanup | Notes |
+|------|------|---------|---------|-------|
+| Image compression | `MediaCompressor.kt:94` | Temp copy via `MediaCompressorFileUtils.from()` | UploadOrchestrator `finally` | Deferred to cache cleanup |
+| Image metadata strip | `MetadataStripper.kt:199` | `stripped_*.jpg` in cacheDir | UploadOrchestrator `finally` | Deferred to cache cleanup |
+| Video metadata strip | `MetadataStripper.kt:238` | `stripped_video_*.mp4` in cacheDir | UploadOrchestrator `finally` | Deferred to cache cleanup |
+| Audio metadata strip | `MetadataStripper.kt:286` | `stripped_audio_*.m4a` in cacheDir | UploadOrchestrator `finally` | Deferred to cache cleanup |
+| MP3 metadata strip | `MetadataStripper.kt:307,363` | `mp3_input_*` + `stripped_mp3_*` | Mixed: some immediate, some orchestrator | MP3 input file cleaned inline |
+| File encryption | `EncryptFiles.kt:47` | `EncryptFiles*.encrypted` in cacheDir | UploadOrchestrator `finally` | Deferred to cache cleanup |
+| URI temp copy | `MediaCompressorFileUtils.kt:41` | Random UUID temp file | Caller-dependent | No self-cleanup |
+| Voice anonymization | `VoiceAnonymizationController.kt:85` | Distorted voice files | `deleteDistortedFiles()` explicit | Cleaned by controller |
+| Video sharing | `ZoomableContentView.kt:905` | Temp video + sharable copy | Delayed GlobalScope (1 min) | Intentional delay for sharing |
+| Camera capture | `TakePicture.kt:244` | Camera temp file | System/caller | Managed by camera provider |
+
+## Temporary File Creation Sites (Desktop)
+
+| Area | File | Creates | Cleanup | Notes |
+|------|------|---------|---------|-------|
+| Clipboard paste | `ClipboardPasteHandler.kt:43` | `clipboard_*.png` | `deleteOnExit()` only | Leaks until JVM exit |
+| Image compression | `DesktopMediaCompressor.kt:42` | `stripped_*.jpg` | `deleteOnExit()` only | Leaks until JVM exit |
+
+## The Upload Pipeline
+
+The `UploadOrchestrator` is the central cleanup coordinator. Its `finally` blocks call
+`deleteTempUri()` to delete intermediate files after upload completes. The pipeline stages:
+
+```
+1. MediaCompressorFileUtils.from()  --> temp copy of original URI
+2. MediaCompressor.compress()       --> compressed file (may replace #1)
+3. MetadataStripper.strip*()        --> stripped file (new temp)
+4. (optional) EncryptFiles.encrypt() --> encrypted file (new temp)
+5. Upload to server
+6. finally: delete all intermediates via deleteTempUri()
+```
+
+Each stage may produce a new temp file. Currently, all intermediates accumulate and are
+only cleaned up in the `finally` block after the upload succeeds or fails.
+
+## Cleanup Patterns in Use
+
+### 1. Chained Deletion (UploadOrchestrator)
+- Most common pattern
+- `finally` blocks at `L374-379` (upload) and `L410-415` (uploadEncrypted)
+- Deletes all intermediate temp files after pipeline completes
+- Checks `tempUri != originalUri` to avoid deleting user's original file
+
+### 2. Delayed Deletion (Video Sharing)
+- `ZoomableContentView.kt:953-960`
+- Uses `GlobalScope.launch(Dispatchers.IO)` with 1 minute delay
+- Intentional: allows recipient app time to read the shared file
+- **Exception: this delay is necessary and should not be shortened**
+
+### 3. Explicit Cleanup Calls (Voice)
+- `VoiceAnonymizationController.deleteDistortedFiles()` at `L108-123`
+- Called explicitly by `ShortNotePostViewModel` at `L1336`
+- Good pattern: controller owns its temp files
+
+### 4. deleteOnExit() (Desktop)
+- Used by `ClipboardPasteHandler` and `DesktopMediaCompressor`
+- Files persist until JVM process exits
+- Not ideal for long-running desktop app
+
+## Opportunities for More Aggressive Cleanup
+
+### 1. Pipeline Stage Cleanup (UploadOrchestrator)
+
+**Current:** All intermediates deleted in `finally` after upload.
+
+**Proposed:** Delete each intermediate as soon as the next stage produces output.
+
+Example: after `MetadataStripper` produces a stripped file, delete the compressed file
+from the previous stage immediately, rather than keeping it alive through upload + finally.
+
+### 2. Desktop Temp Files
+
+**Current:** `deleteOnExit()` — files persist for entire app session.
+
+**Proposed:** Delete immediately after upload completes, matching the Android
+`UploadOrchestrator` pattern via `DesktopUploadOrchestrator`.
+
+### 3. MediaCompressorFileUtils Intermediate
+
+**Current:** `from()` creates a temp copy at `L41`. If compression produces a *different*
+file, the original temp copy is orphaned until `UploadOrchestrator.finally`.
+
+**Proposed:** `MediaCompressor` should delete the `from()` temp file immediately after
+compression succeeds (when the compressed file differs from the input).
+
+### 4. Voice Anonymization Intermediates
+
+**Current:** `deleteDistortedFiles()` called after upload.
+
+**Proposed:** Already reasonably aggressive. Could delete each intermediate distortion
+result as soon as the next processing step completes, if there are multiple stages.
+
+## Exception: Video Sharing
+
+Sharing a video to other Android apps requires the temporary file to remain accessible
+for at least 1 minute. The current `SHARED_VIDEO_CLEANUP_DELAY_MS` delay in
+`ZoomableContentView.kt` handles this correctly and should **not** be made more aggressive.