fix: prevent race condition in camera buffer management

[thesohamdatta]

Add safety check in take_photo() to prevent capturing while upload
is in progress. This fixes potential memory corruption and crashes
during continuous photo capture operations.

[gemini-code-assist]

Code Review

The pull request introduces a safety check in the take_photo() function to prevent capturing while a photo upload is in progress, which is a good step towards preventing race conditions and memory corruption. However, the effectiveness of this fix relies heavily on the thread-safety of the photoDataUploading flag. If this flag is a shared global variable and modified by multiple tasks, its access needs proper synchronization to truly prevent race conditions in a multi-tasking environment, aligning with the rule that global variables are only safe without thread-safe accessors if modified by a single thread.

[gemini-code-assist]

The photoDataUploading flag is used here to prevent a race condition. However, if photoDataUploading is a global boolean variable modified by another task (e.g., the photo upload task) and read by this function, its access needs to be synchronized (e.g., using a mutex or std::atomic_bool) to ensure thread-safety. Without proper synchronization, a data race could still occur, leading to inconsistent state and potentially memory corruption, which this PR aims to prevent. This is a critical issue for the reliability of the system.

References

1. This rule implies that for shared variables that are modified and read by multiple tasks, a critical section (or other synchronization mechanism) is necessary to prevent race conditions and ensure data consistency.