@include <SharedStack>

The SharedStack class provides a stack implementation that shares its state across multiple instances. This class is useful for scenarios in which we’re forking processes and need a shared stack between them.

Reads and writes are atomic and concurrency-safe.

The stack can be encrypted for security.

Internally, it uses the file system to store the stack state.

Methods

@SharedStack.size

Scope: public

Echoes the number of elements in the stack.

Usage: @SharedStack.size

@SharedStack.push

Scope: public

Pushes a value onto the top of the stack.

Usage: @SharedStack.push $value

Parameters

  • value
    • Type: primitive
    • The value to push onto the top of the stack.

@SharedStack.pop

Scope: public

Pops the top element off the stack and echoes it.

Usage: @SharedStack.pop

@SharedStack.top

Scope: public

Echoes the top element of the stack without removing it.

Usage: @SharedStack.top

@SharedStack.clear

Scope: public

Removes all elements from the stack.

Usage: @SharedStack.clear

@SharedStack.empty

Scope: public

Echoes “true” if the stack is empty, “false” otherwise.

Usage: @SharedStack.empty

@SharedStack.setEncrypted

Scope: public

Sets whether the object should be encrypted. Encrypting the object can mitigate unauthorized reads by other processes.

This cannot be changed after the object has been used.

Usage: @SharedStack.setEncrypted $value

Parameters

  • value
    • Type: primitive
    • ‘1’ or ‘true’ enables encryption, any other value disables it.

@SharedStack.lock

Scope: public

Locks the shared object for exclusive access.

Once locked, only the process which locked it can access the object until it is unlocked.

Attempts by other processes access the object while it is locked will block until it is unlocked.

Using this method (as opposed to the internal _lock method) sets the extended_lock flag to 1, indicating that the lock should not be dropped until explicitly unlocked. I.e., subsequent calls to _unlock (internal) will not release the lock until unlock (public) is called.

Usage: @SharedStack.lock

@SharedStack.unlock

Scope: public

Unlocks the shared object, allowing other processes to access it.

This also resets the extended_lock flag to 0.

Usage: @SharedStack.unlock