Start migrating I/O writers to pylibcudf (starting with JSON)

docs/cudf/source/user_guide/api_docs/pylibcudf/io/index.rst

@@ -16,3 +16,4 @@ I/O Functions
     :maxdepth: 1
 
     avro
+    json

docs/cudf/source/user_guide/api_docs/pylibcudf/io/json.rst

@@ -0,0 +1,6 @@
+====
+JSON
+====
+
+.. automodule:: cudf._lib.pylibcudf.io.json
+   :members:

python/cudf/cudf/_lib/json.pyx

@@ -9,38 +9,27 @@ from cudf.core.buffer import acquire_spill_lock
 
 from libcpp cimport bool
 from libcpp.map cimport map
-from libcpp.memory cimport unique_ptr
 from libcpp.string cimport string
 from libcpp.utility cimport move
 from libcpp.vector cimport vector
 
 cimport cudf._lib.pylibcudf.libcudf.io.types as cudf_io_types
-from cudf._lib.column cimport Column
-from cudf._lib.io.utils cimport (
-    make_sink_info,
-    make_source_info,
-    update_struct_field_names,
-)
-from cudf._lib.pylibcudf.libcudf.io.data_sink cimport data_sink
+from cudf._lib.io.utils cimport make_source_info, update_struct_field_names
 from cudf._lib.pylibcudf.libcudf.io.json cimport (
     json_reader_options,
     json_recovery_mode_t,
-    json_writer_options,
     read_json as libcudf_read_json,
     schema_element,
-    write_json as libcudf_write_json,
 )
 from cudf._lib.pylibcudf.libcudf.io.types cimport (
-    column_name_info,
     compression_type,
-    sink_info,
-    table_metadata,
     table_with_metadata,
 )
-from cudf._lib.pylibcudf.libcudf.table.table_view cimport table_view
 from cudf._lib.pylibcudf.libcudf.types cimport data_type, size_type
 from cudf._lib.types cimport dtype_to_data_type
-from cudf._lib.utils cimport data_from_unique_ptr, table_view_from_table
+from cudf._lib.utils cimport data_from_unique_ptr
+
+import cudf._lib.pylibcudf as plc
 
 
 cdef json_recovery_mode_t _get_json_recovery_mode(object on_bad_lines):
@@ -175,45 +164,27 @@ def write_json(
     --------
     cudf.to_json
     """
-    cdef table_view input_table_view = table_view_from_table(
-        table, ignore_index=True
-    )
-
-    cdef unique_ptr[data_sink] data_sink_c
-    cdef sink_info sink_info_c = make_sink_info(path_or_buf, data_sink_c)
-    cdef string na_c = na_rep.encode()
-    cdef bool include_nulls_c = include_nulls
-    cdef bool lines_c = lines
-    cdef int rows_per_chunk_c = rows_per_chunk
-    cdef string true_value_c = 'true'.encode()
-    cdef string false_value_c = 'false'.encode()
-    cdef table_metadata tbl_meta
-
-    num_index_cols_meta = 0
-    cdef column_name_info child_info
-    for i, name in enumerate(table._column_names, num_index_cols_meta):
-        child_info.name = name.encode()
-        tbl_meta.schema_info.push_back(child_info)
-        _set_col_children_metadata(
-            table[name]._column,
-            tbl_meta.schema_info[i]
-        )
+    cdef list colnames = []
 
-    cdef json_writer_options options = move(
-        json_writer_options.builder(sink_info_c, input_table_view)
-        .metadata(tbl_meta)
-        .na_rep(na_c)
-        .include_nulls(include_nulls_c)
-        .lines(lines_c)
-        .rows_per_chunk(rows_per_chunk_c)
-        .true_value(true_value_c)
-        .false_value(false_value_c)
-        .build()
-    )
+    for name in table._column_names:
+        colnames.append((name, _dtype_to_names_list(table[name]._column)))
 
     try:
-        with nogil:
-            libcudf_write_json(options)
+        plc.io.json.write_json(
+            plc.io.SinkInfo([path_or_buf]),
+            plc.io.TableWithMetadata(
+                plc.Table([
+                    c.to_pylibcudf(mode="read") for c in table._columns
+                ]),
+                colnames
+            ),
+            na_rep,
+            include_nulls,
+            lines,
+            rows_per_chunk,
+            true_value="true",
+            false_value="false"
+        )
     except OverflowError:
         raise OverflowError(
             f"Writing JSON file with rows_per_chunk={rows_per_chunk} failed. "
@@ -254,23 +225,12 @@ cdef data_type _get_cudf_data_type_from_dtype(object dtype) except *:
         )
     return dtype_to_data_type(dtype)
 
-cdef _set_col_children_metadata(Column col,
-                                column_name_info& col_meta):
-    cdef column_name_info child_info
+
+def _dtype_to_names_list(col):
     if isinstance(col.dtype, cudf.StructDtype):
-        for i, (child_col, name) in enumerate(
-            zip(col.children, list(col.dtype.fields))
-        ):
-            child_info.name = name.encode()
-            col_meta.children.push_back(child_info)
-            _set_col_children_metadata(
-                child_col, col_meta.children[i]
-            )
+        return [(name, _dtype_to_names_list(child))
+                for name, child in zip(col.dtype.fields, col.children)]
     elif isinstance(col.dtype, cudf.ListDtype):
-        for i, child_col in enumerate(col.children):
-            col_meta.children.push_back(child_info)
-            _set_col_children_metadata(
-                child_col, col_meta.children[i]
-            )
-    else:
-        return
+        return [("", _dtype_to_names_list(child))
+                for child in col.children]
+    return []

python/cudf/cudf/_lib/pylibcudf/io/CMakeLists.txt

@@ -12,7 +12,7 @@
 # the License.
 # =============================================================================
 
-set(cython_sources avro.pyx datasource.pyx types.pyx)
+set(cython_sources avro.pyx datasource.pyx json.pyx types.pyx)
 
 set(linked_libraries cudf::cudf)
 rapids_cython_create_modules(
@@ -21,5 +21,7 @@ rapids_cython_create_modules(
   LINKED_LIBRARIES "${linked_libraries}" MODULE_PREFIX pylibcudf_io_ ASSOCIATED_TARGETS cudf
 )
 
-set(targets_using_arrow_headers pylibcudf_io_avro pylibcudf_io_datasource pylibcudf_io_types)
+set(targets_using_arrow_headers pylibcudf_io_avro pylibcudf_io_datasource pylibcudf_io_json
+                                pylibcudf_io_types
+)
 link_to_pyarrow_headers("${targets_using_arrow_headers}")

python/cudf/cudf/_lib/pylibcudf/io/__init__.pxd

@@ -1,4 +1,4 @@
 # Copyright (c) 2024, NVIDIA CORPORATION.
 
-from . cimport avro, datasource, types
+from . cimport avro, datasource, json, types
 from .types cimport SourceInfo, TableWithMetadata

python/cudf/cudf/_lib/pylibcudf/io/__init__.py

@@ -1,4 +1,4 @@
 # Copyright (c) 2024, NVIDIA CORPORATION.
 
-from . import avro, datasource, types
-from .types import SourceInfo, TableWithMetadata
+from . import avro, datasource, json, types
+from .types import SinkInfo, SourceInfo, TableWithMetadata

python/cudf/cudf/_lib/pylibcudf/io/avro.pyx

@@ -19,7 +19,7 @@ cpdef TableWithMetadata read_avro(
     size_type num_rows = -1
 ):
     """
-    Reads an Avro dataset into a set of columns.
+    Reads an Avro dataset into a :py:class:`~.types.TableWithMetadata`.
 
     Parameters
     ----------
@@ -36,7 +36,7 @@ cpdef TableWithMetadata read_avro(
     Returns
     -------
     TableWithMetadata
-        The Table and its corresponding metadata that was read in.
+        The Table and its corresponding metadata (column names) that were read in.
     """
     cdef vector[string] c_columns
     if columns is not None and len(columns) > 0:

python/cudf/cudf/_lib/pylibcudf/io/json.pxd

@@ -0,0 +1,18 @@
+# Copyright (c) 2024, NVIDIA CORPORATION.
+
+from libcpp cimport bool
+
+from cudf._lib.pylibcudf.io.types cimport SinkInfo, TableWithMetadata
+from cudf._lib.pylibcudf.libcudf.types cimport size_type
+
+
+cpdef void write_json(
+    SinkInfo sink_info,
+    TableWithMetadata tbl,
+    str na_rep = *,
+    bool include_nulls = *,
+    bool lines = *,
+    size_type rows_per_chunk = *,
+    str true_value = *,
+    str false_value = *
+)

python/cudf/cudf/_lib/pylibcudf/io/json.pyx

@@ -0,0 +1,68 @@
+# Copyright (c) 2024, NVIDIA CORPORATION.
+
+from libcpp cimport bool
+from libcpp.limits cimport numeric_limits
+from libcpp.string cimport string
+
+from cudf._lib.pylibcudf.io.types cimport SinkInfo, TableWithMetadata
+from cudf._lib.pylibcudf.libcudf.io.json cimport (
+    json_writer_options,
+    write_json as cpp_write_json,
+)
+from cudf._lib.pylibcudf.libcudf.io.types cimport table_metadata
+from cudf._lib.pylibcudf.types cimport size_type
+
+
+cpdef void write_json(
+    SinkInfo sink_info,
+    TableWithMetadata table_w_meta,
+    str na_rep = "",
+    bool include_nulls = False,
+    bool lines = False,
+    size_type rows_per_chunk = numeric_limits[size_type].max(),
+    str true_value = "true",
+    str false_value = "false"
+):
+    """
+    Writes a :py:class:`~cudf._lib.pylibcudf.table.Table` to JSON format.
+
+    Parameters
+    ----------
+    sink_info: SinkInfo
+        The SinkInfo object to write the JSON to.
+    table_w_meta: TableWithMetadata
+        The TableWithMetadata object containing the Table to write
+    na_rep: str, default ""
+        The string representation for null values.
+    include_nulls: bool, default False
+        Enables/Disables output of nulls as 'null'.
+    lines: bool, default False
+        If `True`, write output in the JSON lines format.
+    rows_per_chunk: size_type, defaults to length of the input table
+        The maximum number of rows to write at a time.
+    true_value: str, default "true"
+        The string representation for values != 0 in INT8 types.
+    false_value: str, default "false"
+        The string representation for values == 0 in INT8 types.
+    """
+    cdef table_metadata tbl_meta = table_w_meta.metadata
+    cdef string na_rep_c = na_rep.encode()
+
+    cdef json_writer_options options = (
+        json_writer_options.builder(sink_info.c_obj, table_w_meta.tbl.view())
+        .metadata(tbl_meta)
+        .na_rep(na_rep_c)
+        .include_nulls(include_nulls)
+        .lines(lines)
+        .build()
+    )
+
+    if rows_per_chunk != numeric_limits[size_type].max():
+        options.set_rows_per_chunk(rows_per_chunk)
+    if true_value != "true":
+        options.set_true_value(<string>true_value.encode())
+    if false_value != "false":
+        options.set_false_value(<string>false_value.encode())
+
+    with nogil:
+        cpp_write_json(options)

python/cudf/cudf/_lib/pylibcudf/io/types.pxd

@@ -1,4 +1,8 @@
 # Copyright (c) 2024, NVIDIA CORPORATION.
+from libcpp.memory cimport unique_ptr
+from libcpp.vector cimport vector
+
+from cudf._lib.pylibcudf.libcudf.io.data_sink cimport data_sink
 from cudf._lib.pylibcudf.libcudf.io.types cimport (
     column_encoding,
     column_in_metadata,
@@ -22,8 +26,15 @@ cdef class TableWithMetadata:
     cdef public Table tbl
     cdef table_metadata metadata
 
+    cdef vector[column_name_info] _make_column_info(self, list column_names)
+
     @staticmethod
     cdef TableWithMetadata from_libcudf(table_with_metadata& tbl)
 
 cdef class SourceInfo:
     cdef source_info c_obj
+
+cdef class SinkInfo:
+    # This vector just exists to keep the unique_ptrs to the sinks alive
+    cdef vector[unique_ptr[data_sink]] sink_storage
+    cdef sink_info c_obj