fix: ensure that a CCCD is only create once for a characteristic - #128
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tauu wants to merge 1 commit into
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fix: ensure that a CCCD is only create once for a characteristic#128tauu wants to merge 1 commit into
tauu wants to merge 1 commit into
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This PR fixes an issue where multiple CCCDs are created for a characteristic which is not allowed according to the bluetooth specs and break notify / indicate handling on some platforms (e.g. WebBluetooth in Chrome).
The error occurs when AddService(...) is called multiple times in a row, as for each call a new database is created. This in turn will create the attributes for each service (also already added ones). During the attribute creation a CCCD is created when a characteristic has a notify or indicate handler and it is added to the datastructure of the characteristic. During that it is not checked if the characteristic already has a CCCD. Therefore a characteristic ends up with multiple CCCDs if attributes for it are created more than once.
The PR fixes this by first checking if a CCCD already exists.