Cache

class understand.Cache

Bases: object

Cache object

This object can be retrieved from plugin objects and allows plugin scripts to store, retrieve, and share data. It’s essentially a global variable whose lifetime is managed by Understand. At minimum, caches are cleared when the corresponding database is analyzed or closed, but may be cleared more frequently.

Understand maintains a read-only Git cache (retrieved with id=”Git”) that supports the following keys:

cache.value(ent=file,key=”commits”) # List of commits from newest to oldest cache.value(ent=file,key=”authors”) # List of authors corresponding to commits cache.value(ent=file,key=”dates”) # List of iso date strings corresponding to commits

Methods Summary

clear	Clear the cache.
insert	Store a value in the cache.
is_empty	Return True if the cache is empty
lock	Lock the cache.
unlock	cache.lock() -> None
value	Return the value stored under key and/or entity.

Methods Documentation

clear() → None

Clear the cache. Caches are cleared automatically by Understand so scripts won’t normally need to call this unless data external to Understand changes.

Return type:

None

insert(value[, key[, ent]]) → None

Store a value in the cache. Optionally specify a string and/or an entity as keys. The value can be retrieved with value. Supported values are entities, strings, integers, doubles, and lists of the supported values.

Parameters:

• value (str or int or double or list) – the value to store

• key (str) – optional, a string identifier

• ent (understand.Ent) – optional, an entity identifier

Returns:

the the stored value

is_empty() → bool

Return True if the cache is empty

Return type:

bool

Returns:

True if the cache is empty

lock() → None

Lock the cache. Careful: users must call unlock()!

Calls reading and writing from the cache are protected for access from multiple threads. This function is only for clients that need additional control over thread access. For example, a CodeCheck script that calculates an entire cache globally could use this function to ensure that other CodeCheck threads block instead of simultaneously performing the expensive calculation.

If lock() is called, unlock() MUST be called.

Return type:

None

unlock()

cache.lock() -> None

Unlock the cache. Careful: users must have called lock() first!

Calls reading and writing from the cache are protected for access from multiple threads. This function is only for clients that need additional control over thread access. For example, a CodeCheck script that calculates an entire cache globally could use this function to ensure that other CodeCheck threads block instead of simultaneously performing the expensive calculation.

The lock() call must be called before this call.

Return type:

None

value([key[, ent[, value]]]) → value

Return the value stored under key and/or entity. See insert for saveable values. Use the value parameter to give a return value when the key/entity is not in the cache. The value parameter defaults to None.

Parameters:

• key (str) – optional, a string identifier

• ent (understand.Ent) – optional, an entity identifier

• value – optional, a return value if the key/entity pair was not in the cache

Returns:

the stored value or None if none stored