fix(spm): improved dataset type checking

cryosparc/column.py

@@ -52,7 +52,9 @@ def __new__(cls, field: Field, data: Data):
         dtype = n.dtype(fielddtype(field))
         nrow = data.nrow()
         shape = (nrow, *dtype.shape)
-        buffer = data.getbuf(field[0]).memview if nrow else None
+        buffer = data.getbuf(field[0])
+        if buffer is not None:
+            buffer = buffer.memview
         obj = super().__new__(cls, shape=shape, dtype=dtype.base, buffer=buffer)  # type: ignore
 
         # Keep a reference to the data so that it only gets cleaned up when all

cryosparc/core.pyi

@@ -0,0 +1,81 @@
+from enum import Enum
+from typing import SupportsBytes
+
+from numpy.typing import NDArray
+
+__all__ = ["DsetType", "Stream", "Data"]
+
+class MemoryView(SupportsBytes):  # Note: Supports buffer protocol.
+    base: "Array"
+    size: int
+    itemsize: int
+    nbytes: int
+    ndim: int
+    shape: tuple[int, ...]
+    strides: tuple[int, ...]
+    suboffsets: tuple[int, ...]
+    T: "MemoryView"
+
+    def copy(self) -> "MemoryView": ...
+    def copy_fortran(self) -> "MemoryView": ...
+    def is_c_contig(self) -> bool: ...
+    def is_f_contig(self) -> bool: ...
+
+class Array:
+    memview: MemoryView
+
+    def __len__(self) -> int: ...
+    def __getitem__(self, key: int | slice) -> bytes: ...
+    def __setitem__(self, key: int | slice, item: bytes): ...
+
+class DsetType(int, Enum):
+    T_F32 = ...
+    T_F64 = ...
+    T_C32 = ...
+    T_C64 = ...
+    T_I8 = ...
+    T_I16 = ...
+    T_I32 = ...
+    T_I64 = ...
+    T_U8 = ...
+    T_U16 = ...
+    T_U32 = ...
+    T_U64 = ...
+    T_STR = ...
+    T_OBJ = ...
+
+class Data:
+    def __init__(self, other: "Data" | None = None) -> None: ...
+    def innerjoin(self, key: str, other: "Data") -> "Data": ...
+    def totalsz(self) -> int: ...
+    def ncol(self) -> int: ...
+    def nrow(self) -> int: ...
+    def key(self, index: int) -> str: ...
+    def type(self, field: str) -> int: ...
+    def has(self, field: str) -> bool: ...
+    def addrows(self, num: int) -> None: ...
+    def addcol_scalar(self, field: str, dtype: int) -> None: ...
+    def addcol_array(self, field: str, dtype: int, shape: tuple[int, ...]) -> None: ...
+    def getshp(self, colkey: str) -> tuple[int, ...]: ...
+    def getbuf(self, colkey: str) -> Array | None: ...
+    def getstr(self, col: str, index: int) -> bytes: ...
+    def tocstrs(self, col: str) -> bool: ...
+    def topystrs(self, col: str) -> bool: ...
+    def stralloc(self, val: str) -> int: ...
+    def dump(self) -> Array: ...
+    def dumpstrheap(self) -> Array: ...
+    def setstrheap(self, heap: bytes) -> None: ...
+    def defrag(self, realloc_smaller: bool) -> None: ...
+    def dumptxt(self, dump_data: bool = False) -> None: ...
+    def handle(self) -> int: ...
+
+class Stream:
+    def __init__(self, data: Data) -> None: ...
+    def cast_objs_to_strs(self) -> None: ...
+    def stralloc_col(self, col: str) -> Array | None: ...
+    def compress_col(self, col: str) -> Array: ...
+    def compress_numpy(self, arr: NDArray) -> Array: ...
+    def compress(self, arr: Array) -> Array: ...
+    def decompress_col(self, col: str, data: bytes) -> Array: ...
+    def decompress_numpy(self, data: bytes, arr: NDArray) -> Array: ...
+    def decompress(self, data: bytes, outptr: int = 0) -> Array: ...

cryosparc/core.pyx

@@ -142,7 +142,7 @@ cdef class Data:
         with nogil:
             mem = dataset.dset_get(self._handle, colkey_c)
             size = dataset.dset_getsz(self._handle, colkey_c)
-        return 0 if size == 0 else <unsigned char [:size]> mem
+        return None if size == 0 else <unsigned char [:size]> mem
 
     def getstr(self, str col, size_t index):
         return dataset.dset_getstr(self._handle, col.encode(), index)  # returns bytes

cryosparc/dataset.py

@@ -75,8 +75,6 @@
 if TYPE_CHECKING:
     from numpy.typing import ArrayLike, DTypeLike, NDArray
 
-    from .core import MemoryView
-
 
 # Save format options
 NUMPY_FORMAT = 1
@@ -683,16 +681,17 @@ def _load_stream(
         descr = filter_descr(header["dtype"], keep_prefixes=prefixes, keep_fields=fields)
         field_names = {field[0] for field in descr}
 
-        # Calling addrows separately to minimizes column-based
-        # allocations, improves performance by ~20%
+        # Calling addrows separately to minimize column-based allocations,
+        # improves performance by ~20%
         dset = cls.allocate(0, descr)
-        if header["length"] == 0:
-            return dset  # no more data to load
-
         data = dset._data
         data.addrows(header["length"])
+
+        # If a dataset is empty, it won't have anything in its data section.
+        # Just the string heap at the end.
+        dtype = [] if header["length"] == 0 else header["dtype"]
         loader = Stream(data)
-        for field in header["dtype"]:
+        for field in dtype:
             colsize = u32intle(f.read(4))
             if field[0] not in field_names:
                 # try to seek instead of read to reduce memory usage
@@ -701,8 +700,10 @@ def _load_stream(
             buffer = f.read(colsize)
             if field[0] in header["compressed_fields"]:
                 loader.decompress_col(field[0], buffer)
-            else:
-                data.getbuf(field[0])[:] = buffer
+                continue
+            mem = data.getbuf(field[0])
+            assert mem is not None, f"Could not load stream (missing {field[0]} buffer)"
+            mem[:] = buffer
 
         # Read in the string heap (rest of stream)
         # NOTE: There will be a bug here for long column keys that are
@@ -726,16 +727,22 @@ async def from_async_stream(cls, stream: AsyncBinaryIO):
         dset = cls.allocate(0, header["dtype"])
         data = dset._data
         data.addrows(header["length"])
+
+        # If a dataset is empty, it won't have anything in its data section.
+        # Just the string heap at the end.
+        dtype = [] if header["length"] == 0 else header["dtype"]
         loader = Stream(data)
-        for field in header["dtype"]:
+        for field in dtype:
             colsize = u32intle(await stream.read(4))
             buffer = await stream.read(colsize)
             if field[0] in header["compressed_fields"]:
                 loader.decompress_col(field[0], buffer)
-            else:
-                data.getbuf(field[0])[:] = buffer
+                continue
+            mem = data.getbuf(field[0])
+            assert mem is not None, f"Could not load stream (missing {field[0]} buffer)"
+            mem[:] = buffer
 
-        heap = stream.read()
+        heap = await stream.read()
         data.setstrheap(heap)
 
         # Convert C strings to Python strings
@@ -803,16 +810,14 @@ def stream(self, compression: Literal["lz4", None] = None) -> Generator[bytes, N
         yield u32bytesle(len(header))
         yield header
 
-        if len(self) == 0:
-            return  # empty dataset, don't yield anything
-
-        for f in self:
-            fielddata: "MemoryView"
+        fields = [] if len(self) == 0 else self.fields()
+        for f in fields:
             if f in compressed_fields:
                 # obj columns added to strheap and loaded as indexes
                 fielddata = stream.compress_col(f)
             else:
                 fielddata = stream.stralloc_col(f) or data.getbuf(f)
+            assert fielddata is not None, f"Could not stream dataset (missing {f} buffer)"
             yield u32bytesle(len(fielddata))
             yield bytes(fielddata.memview)
 
@@ -1231,7 +1236,7 @@ def filter_prefix(self, keep_prefix: str, *, rename: Optional[str] = None, copy:
         if rename and rename != keep_prefix:
             new_fields = [f"{rename}/{f.split('/', 1)[1]}" for f in keep_fields]
 
-        result = type(self)([("uid", self["uid"])] + [(nf, self[f]) for f, nf in zip(keep_fields, new_fields)])
+        result = type(self)([("uid", self["uid"])] + [(nf, self[f]) for f, nf in zip(keep_fields, new_fields)])  # type: ignore
         return result if copy else self._reset(result._data)
 
     def drop_fields(self, names: Union[Collection[str], Callable[[str], bool]], *, copy: bool = False):