LazyStorage holds the blocks of a remote file fetched so far. An
operation runs as passes over it: a read that misses records the
missing blocks and fails, the pass's result is dropped whatever it is
(a parser may have caught the error and carried on), and the caller
fetches the reported ranges and re-runs the pass. No block is evicted
while an operation is in flight, so every pass that does not finish
asks for at least one new block and the operation ends. Blocks sit in
an LRU with a byte budget, trimmed between operations, bulk (raw data)
blocks first.
Reader::open_storage opens a file through any Storage, and variable-
length strings resolve through the file's storage instead of
File::as_bytes, which panics for a file not in memory.
tests/lazy.rs compares, file by file, what the viewer can show (kinds,
listings, attributes, info, whole reads and hyperslabs) read lazily
with the facade's range-storage path and the in-memory reader: files
built here at 512 B to 1 MiB blocks, the h5py/netCDF4 fixture, and with
CLAWHDF5_WASM_CORPUS the conformance corpus (656 files agree). A
listing plus a small read of a 48 MB file fetches 3 ranges.
Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
