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Replace `LMDB.mdb_unpack(::Type{T}, ::Ref{MDB_val})` — the package's
typed-read customization point — with a plain `IO` view over the
LMDB-owned `MDB_val`. Users now plug in custom decoders by defining
the idiomatic `Base.read(io::IO, ::Type{MyType})`, which works against
any byte stream and is the convention every other Julia decoder uses.
struct PrefixedBlob end
function Base.read(io::IO, ::Type{PrefixedBlob})
skip(io, 8)
return read(io, String)
end
LMDB.tryget(txn, dbi, key, PrefixedBlob)
`MDBValueIO <: IO` exposes `position` / `seek` / `seekstart` / `seekend`
/ `skip` / `bytesavailable` / `eof` and overrides `unsafe_read` so
Base's primitive `read(io, T)` for `Int8…Float64`/`Bool`/`Char`/`Ptr`
inherits zero-allocation. The default `read(io, String)` and
`read(io, Vector{E})` consume the rest of the buffer and copy out.
Internal call sites in `cur.jl` / `dbi.jl` / `dicts.jl` switch from
`mdb_unpack(T, ref)` to `read(MDBValueIO(ref[]), T)`. The package
exposes `LMDB.MDBValueIO` for users who override `Base.read`.
`mdb_unpack` is dropped — breaking change for the (rare) caller who
defined their own `mdb_unpack` method.
Preserves PR #52's GC-safety fix: `common.jl` keeps the
deferred-pointer-extraction pattern from #52 (the upstream commit
this is based on pre-dates that fix). `MDBValue(::String)` and the
eager-extraction variants stay deleted; `cconvert(::Ptr{MDB_val}, x)`
returns an `MDBArg` carrier with an uninitialized box, and
`unsafe_convert(::Ptr{MDB_val}, ::MDBArg{D})` does the extraction
inside ccall's preserve window.
Tested locally on Julia 1.10, 1.11, 1.12, 1.13.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Codecov Report❌ Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## main #55 +/- ##
==========================================
- Coverage 83.40% 82.11% -1.29%
==========================================
Files 9 9
Lines 717 755 +38
==========================================
+ Hits 598 620 +22
- Misses 119 135 +16 ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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Replace
LMDB.mdb_unpack(::Type{T}, ::Ref{MDB_val})— the package's typed-read customization point — with a plainIOview over the LMDB-ownedMDB_val. Users now plug in custom decoders by defining the idiomaticBase.read(io::IO, ::Type{MyType}), which works against any byte stream and is the convention every other Julia decoder uses.MDBValueIO <: IOexposesposition/seek/seekstart/seekend/skip/bytesavailable/eofand overridesunsafe_readso Base's primitiveread(io, T)forInt8…Float64/Bool/Char/Ptrinherits zero-allocation. The defaultread(io, String)andread(io, Vector{E})consume the rest of the buffer and copy out.Internal call sites in
cur.jl/dbi.jl/dicts.jlswitch frommdb_unpack(T, ref)toread(MDBValueIO(ref[]), T). The package exposesLMDB.MDBValueIOfor users who overrideBase.read.Last piece of functionality I had locally, will focus on cleaning up things tomorrow.