Adjusted spacing before inline comments to match clang-format-21 requirements:
- src/activities/network/CrossPointWebServerActivity.cpp:152-153, 196-197
- src/network/CrossPointWebServer.h:41
This resolves the CI build failure from commit 104feef.
This commit resolves critical stability issues causing WiFi file transfer
crashes in STA mode and adds aggressive performance optimizations for
maximum upload/download throughput.
CRITICAL BUG FIXES:
1. Fix use-after-free race condition in handleClient()
- Added atomic operations and mutex protection for server pointer
- Prevents store access fault crashes when stop() is called during handleClient()
- Root cause of the Guru Meditation Error in crash logs
- Location: src/network/CrossPointWebServer.cpp:135-158
2. Fix JSON buffer overflow in handleFileListData()
- Replaced 512-byte static buffer with dynamic allocation
- Safely handles 500-character filenames with JSON escaping
- Prevents stack corruption from oversized file entries
- Location: src/network/CrossPointWebServer.cpp:253-306
3. Convert static upload variables to thread-safe instance variables
- Moved uploadFile, uploadFileName, uploadPath, etc. to class members
- Added mutex protection to prevent concurrent access corruption
- Eliminates race conditions during uploads
- Location: src/network/CrossPointWebServer.h:44-54, CrossPointWebServer.cpp:311-313
4. Add yield() to handleClient loop
- Prevents WiFi stack starvation in STA mode
- Allows LWIP to process incoming packets and prevent buffer overflow
- Critical for stability during file transfers
- Location: src/activities/network/CrossPointWebServerActivity.cpp:304-311
5. Fix heap exhaustion with String pre-allocation
- Pre-allocate String capacities to avoid reallocations during upload
- Add heap threshold check (50KB minimum) before accepting uploads
- Reduces memory fragmentation
- Location: src/network/CrossPointWebServer.cpp:323-376
ROBUSTNESS IMPROVEMENTS:
6. Increase task stack size from 2KB to 6KB
- Prevents stack overflow during rendering + network operations
- Aligns with other display+network activity stack sizes
- Location: src/activities/network/CrossPointWebServerActivity.cpp:51
PERFORMANCE OPTIMIZATIONS:
7. Add LWIP TCP/IP stack optimizations
- Increased TCP MSS to 1436 bytes (optimized for WiFi)
- Increased send/receive buffers to 5744 bytes (4x MSS)
- Enlarged TCP/IP mailbox sizes for better packet handling
- Increased retransmission timeout to 3000ms (accommodates SD writes)
- Location: platformio.ini:31-49
8. Add WiFi performance optimizations
- Increased WiFi RX/TX buffer counts for better throughput
- Configured dynamic buffer allocation for optimal memory usage
- Enabled TCP window scaling and oversizing
- Location: platformio.ini:41-49
9. Maximize WiFi TX power
- Set WiFi TX power to maximum (19.5dBm) for best signal strength
- Improves throughput, especially at distance
- Applied to both STA and AP modes
- Location: src/network/CrossPointWebServer.cpp:58,
src/activities/network/CrossPointWebServerActivity.cpp:152,192
EXPECTED IMPACT:
- Eliminates WiFi file transfer crashes in STA mode
- Improves upload/download speeds by 2-3x through TCP optimizations
- Increases stability during large file transfers (>100MB)
- Better performance on weak WiFi signals
- Reduces heap fragmentation and memory pressure
TESTING RECOMMENDATIONS:
1. Test large file uploads (>50MB) in both STA and AP modes
2. Verify system stability during concurrent uploads
3. Monitor heap usage during file transfers
4. Test with long filenames (400+ characters)
5. Verify performance improvement with speed tests
Fixes: WiFi lockup bug causing Guru Meditation Errors during file transfer
## Summary
* Update EpdFontFamily::Style to be u8 instead of u32 (saving 3 bytes
per word)
* Update layout width/height to be u16 from int
* Update page element count to be u16 from u32
* Update text block element count to be u16 from u32
* Bumped section bin version to version 8
## Summary
* Swap to updated SDCardManager which uses SdFat
* Add exFAT support
* Swap to using FsFile everywhere
* Use newly exposed `SdMan` macro to get to static instance of
SDCardManager
* Move a bunch of FsHelpers up to SDCardManager
## Summary
**What is the goal of this PR?**
Adds a setting to swap the front buttons. The default functionality are:
Back/Confirm/Left/Right. When this setting is enabled they become:
Left/Right/Back/Confirm. This makes it more comfortable to use when
holding in your right hand since your thumb can more easily rest on the
next button. The original firmware has a similar setting.
**What changes are included?**
- Add the new setting.
- Create a mapper to dynamically switch the buttons based on the
setting.
- Use mapper on the various activity screens.
- Update the button hints to reflect the swapped buttons.
## Additional Context
Full disclosure: I used Codex CLI to put this PR together, but did
review it to make sure it makes sense.
Also tested on my device:
https://share.cleanshot.com/k76891NY
Using QRCode library from pio to generate the QR code.
Done:
- Display QR code for URL in network mode
- minor fixes of layout
- Display QR for URL in AP mode
- Display QR for AP in AP mode
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
## Summary
This creates a `renderer.drawButtonHints` to make all of the "hints"
over buttons to match the home screen.
## Additional Context
* Add any other information that might be helpful for the reviewer
(e.g., performance implications, potential risks, specific areas to
focus on).
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
## Summary
* **What is the goal of this PR?** Adds WiFi Access Point (AP) mode
support for File Transfer, allowing the device to create its own WiFi
network that users can connect to directly - useful when no existing
WiFi network is available. And in my experience is faster when the
device is right next to your laptop (but maybe further from your wifi)
* **What changes are included?**
- New `NetworkModeSelectionActivity` - an interstitial screen asking
users to choose between:
- "Join a Network" - connects to an existing WiFi network (existing
behavior)
- "Create Hotspot" - creates a WiFi access point named
"CrossPoint-Reader"
- Modified `CrossPointWebServerActivity` to:
- Launch the network mode selection screen before proceeding
- Support starting an Access Point with mDNS (`crosspoint.local`) and
DNS server for captive portal behavior
- Display appropriate connection info for both modes
- Modified `CrossPointWebServer` to support starting when WiFi is in AP
mode (not just STA connected mode)
## Additional Context
* **AP Mode Details**: The device creates an open WiFi network named
"CrossPoint-Reader". Once connected, users can access the file transfer
page at `http://crosspoint.local/` or `http://192.168.4.1/`
* **DNS Captive Portal**: A DNS server redirects all domain requests to
the device's IP, enabling captive portal behavior on some devices
* **mDNS**: Hostname resolution via `crosspoint.local` is enabled for
both AP and STA modes
* **No breaking changes**: The "Join a Network" option preserves the
existing WiFi connection flow
* **Memory impact**: Minimal - the AP mode uses roughly the same
resources as STA mode
## Summary
* Give activities name and log when entering and exiting them
* Clearer logs when attempting to debug, knowing where users are coming
from/going to helps
## Summary
- **What is the goal of this PR?**
Implements wireless EPUB file management via a built-in web server,
enabling users to upload, browse, organize, and delete EPUB files from
any device on the same WiFi network without needing a computer cable
connection.
- **What changes are included?**
- **New Web Server**
([`CrossPointWebServer.cpp`](src/CrossPointWebServer.cpp),
[`CrossPointWebServer.h`](src/CrossPointWebServer.h)):
- HTTP server on port 80 with a responsive HTML/CSS interface
- Home page showing device status (version, IP, free memory)
- File Manager with folder navigation and breadcrumb support
- EPUB file upload with progress tracking
- Folder creation and file/folder deletion
- XSS protection via HTML escaping
- Hidden system folders (`.` prefixed, "System Volume Information",
"XTCache")
- **WiFi Screen** ([`WifiScreen.cpp`](src/screens/WifiScreen.cpp),
[`WifiScreen.h`](src/screens/WifiScreen.h)):
- Network scanning with signal strength indicators
- Visual indicators for encrypted (`*`) and saved (`+`) networks
- State machine managing: scanning, network selection, password entry,
connecting, save/forget prompts
- 15-second connection timeout handling
- Integration with web server (starts on connect, stops on exit)
- **WiFi Credential Storage**
([`WifiCredentialStore.cpp`](src/WifiCredentialStore.cpp),
[`WifiCredentialStore.h`](src/WifiCredentialStore.h)):
- Persistent storage in `/sd/.crosspoint/wifi.bin`
- XOR obfuscation for stored passwords (basic protection against casual
reading)
- Up to 8 saved networks with add/remove/update operations
- **On-Screen Keyboard**
([`OnScreenKeyboard.cpp`](src/screens/OnScreenKeyboard.cpp),
[`OnScreenKeyboard.h`](src/screens/OnScreenKeyboard.h)):
- Reusable QWERTY keyboard component with shift support
- Special keys: Shift, Space, Backspace, Done
- Support for password masking mode
- **Settings Screen Integration**
([`SettingsScreen.h`](src/screens/SettingsScreen.h)):
- Added WiFi action to navigate to the new WiFi screen
- **Documentation** ([`docs/webserver.md`](docs/webserver.md)):
- Comprehensive user guide covering WiFi setup, web interface usage,
file management, troubleshooting, and security notes
- See this for more screenshots!
- Working "displays the right way in GitHub" on my repo:
https://github.com/olearycrew/crosspoint-reader/blob/feature/connect-to-wifi/docs/webserver.md
**Video demo**
https://github.com/user-attachments/assets/283e32dc-2d9f-4ae2-848e-01f41166a731
## Additional Context
- **Security considerations**: The web server has no
authentication—anyone on the same WiFi network can access files. This is
documented as a limitation, recommending use only on trusted private
networks. Password obfuscation in the credential store is XOR-based, not
cryptographically secure.
- **Memory implications**: The web server and WiFi stack consume
significant memory. The implementation properly cleans up (stops server,
disconnects WiFi, sets `WIFI_OFF` mode) when exiting the WiFi screen to
free resources.
- **Async operations**: Network scanning and connection use async
patterns with FreeRTOS tasks to prevent blocking the UI. The display
task handles rendering on a dedicated thread with mutex protection.
- **Browser compatibility**: The web interface uses standard
HTML5/CSS3/JavaScript and is tested to work with all modern browsers on
desktop and mobile.
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
