Bufq+dynhds

[icing]

Adding 2 pieces to curl's infrastructure for use in various places:

Adding bufq:

• at init() time configured to hold up to n chunks of m bytes each.
• various methods for reading from and writing to it.
• peek support to get access to buffered data without copy
• pass support to allow buffer flushing on write if it becomes full
• use case: IO buffers for dynamic reads and writes that do not blow up
• distinct from dynbuf in that:
  • it maintains a read position
  • writes on a full bufq return CURLE_AGAIN instead of nuking itself
• Init options:
  • SOFT_LIMIT: allow writes into a full bufq
  • NO_SPARES: free empty chunks right away
  • a bufc_pool that can keep a number of spare chunks to
    be shared between different bufq instances

Adding dynhds:

• a straightforward list of name+value pairs as used for HTTP headers
• headers can be appended dynamically
• headers can be removed again
• headers can be replaced
• headers can be looked up
• http/1.1 formatting into a dynbuf
• configured at init() with limits on header counts and total string sizes
• use case: pass a HTTP request or response around without being version specific
• express a HTTP request without a curl easy handle (used in h2 proxy tunnels)
• future extension possibilities:
  • conversions of dynhds to nghttp2/nghttp3 name+value arrays

[bagder]

Thanks!