Add an interface for abstract SHA types (#37091)

This improves inference greatly in circumstances of partial inference.

stdlib/SHA/src/types.jl

@@ -41,6 +41,21 @@ mutable struct SHA2_512_CTX <: SHA2_CTX
  buffer::Array{UInt8,1}
 end
 
+function Base.getproperty(ctx::SHA2_CTX, fieldname::Symbol)
+ if fieldname === :state
+ return getfield(ctx, :state)::Union{Vector{UInt32},Vector{UInt64}}
+ elseif fieldname === :bytecount
+ return getfield(ctx, :bytecount)::Union{UInt64,UInt128}
+ elseif fieldname === :buffer
+ return getfield(ctx, :buffer)::Vector{UInt8}
+ elseif fieldname === :W
+ return getfield(ctx, :W)::Vector{UInt32}
+ else
+ error("SHA2_CTX has no field ", fieldname)
+ end
+end
+
+
 # Typealias common nicknames for SHA2 family of functions
 const SHA224_CTX = SHA2_224_CTX
 const SHA256_CTX = SHA2_256_CTX
@@ -74,6 +89,20 @@ mutable struct SHA3_512_CTX <: SHA3_CTX
  bc::Array{UInt64,1}
 end
 
+function Base.getproperty(ctx::SHA3_CTX, fieldname::Symbol)
+ if fieldname === :state
+ return getfield(ctx, :state)::Vector{UInt64}
+ elseif fieldname === :bytecount
+ return getfield(ctx, :bytecount)::UInt128
+ elseif fieldname === :buffer
+ return getfield(ctx, :buffer)::Vector{UInt8}
+ elseif fieldname === :bc
+ return getfield(ctx, :bc)::Vector{UInt64}
+ else
+ error("type ", typeof(ctx), " has no field ", fieldname)
+ end
+end
+
 # Define constants via functions so as not to bloat context objects. Yay dispatch!
 
 # Digest lengths for SHA1, SHA2 and SHA3. This is easy to figure out from the typename