[PROTON-1941] Add WritableBuffer API for requesting space when writing complex types

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: proton-j-0.29.0
• Fix Version/s: proton-j-0.30.0
• Component/s: proton-j
• Assignee: Timothy A. Bish
• Reporter: Timothy A. Bish
• Created: 26/Sep/18 19:30
• Updated: 29/May/19 18:51
• Resolved: 26/Sep/18 19:54

Description

Add new optional API to WritableBuffer that allows a complex types that has already computed the encoding size to request that the buffer have at least that amount of writable space left before an attempt to encode into that buffers occurs.  This can result in either an early failure of the encode avoiding encoding when the result is bound to fail or the underlying buffer can increase its capacity to accommodate the incoming writes before they happen which can result in less churn as a buffer tries to grow as the complex type gets encoded into it. 

Issue Links

• causes: PROTON-2057 small/array8 primitive arrays >=128 bytes fail to encode
• causes: PROTON-2058 small/array8 byte array encodes incorrectly due to element count omission