晋太元中,武陵人捕鱼为业。缘溪行,忘路之远近。忽逢桃花林,夹岸数百步,中无杂树,芳草鲜美,落英缤纷。渔人甚异之,复前行,欲穷其林。   林尽水源,便得一山,山有小口,仿佛若有光。便舍船,从口入。初极狭,才通人。复行数十步,豁然开朗。土地平旷,屋舍俨然,有良田、美池、桑竹之属。阡陌交通,鸡犬相闻。其中往来种作,男女衣着,悉如外人。黄发垂髫,并怡然自乐。   见渔人,乃大惊,问所从来。具答之。便要还家,设酒杀鸡作食。村中闻有此人,咸来问讯。自云先世避秦时乱,率妻子邑人来此绝境,不复出焉,遂与外人间隔。问今是何世,乃不知有汉,无论魏晋。此人一一为具言所闻,皆叹惋。余人各复延至其家,皆出酒食。停数日,辞去。此中人语云:“不足为外人道也。”(间隔 一作:隔绝)   既出,得其船,便扶向路,处处志之。及郡下,诣太守,说如此。太守即遣人随其往,寻向所志,遂迷,不复得路。   南阳刘子骥,高尚士也,闻之,欣然规往。未果,寻病终。后遂无问津者。 sh-3ll

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# mypy: allow-untyped-defs, allow-incomplete-defs, allow-untyped-calls
# mypy: no-warn-return-any, allow-any-generics

from __future__ import annotations

import re
from typing import Any
from typing import Optional
from typing import TYPE_CHECKING

from sqlalchemy.sql import sqltypes

from .base import AddColumn
from .base import alter_table
from .base import ColumnComment
from .base import ColumnDefault
from .base import ColumnName
from .base import ColumnNullable
from .base import ColumnType
from .base import format_column_name
from .base import format_server_default
from .base import format_table_name
from .base import format_type
from .base import IdentityColumnDefault
from .base import RenameTable
from .impl import DefaultImpl
from ..util.sqla_compat import compiles

if TYPE_CHECKING:
    from sqlalchemy.dialects.oracle.base import OracleDDLCompiler
    from sqlalchemy.engine.cursor import CursorResult
    from sqlalchemy.sql.schema import Column


class OracleImpl(DefaultImpl):
    __dialect__ = "oracle"
    transactional_ddl = False
    batch_separator = "/"
    command_terminator = ""
    type_synonyms = DefaultImpl.type_synonyms + (
        {"VARCHAR", "VARCHAR2"},
        {"BIGINT", "INTEGER", "SMALLINT", "DECIMAL", "NUMERIC", "NUMBER"},
        {"DOUBLE", "FLOAT", "DOUBLE_PRECISION"},
    )
    identity_attrs_ignore = ()

    def __init__(self, *arg, **kw) -> None:
        super().__init__(*arg, **kw)
        self.batch_separator = self.context_opts.get(
            "oracle_batch_separator", self.batch_separator
        )

    def _exec(self, construct: Any, *args, **kw) -> Optional[CursorResult]:
        result = super()._exec(construct, *args, **kw)
        if self.as_sql and self.batch_separator:
            self.static_output(self.batch_separator)
        return result

    def compare_server_default(
        self,
        inspector_column,
        metadata_column,
        rendered_metadata_default,
        rendered_inspector_default,
    ):
        if rendered_metadata_default is not None:
            rendered_metadata_default = re.sub(
                r"^\((.+)\)$", r"\1", rendered_metadata_default
            )

            rendered_metadata_default = re.sub(
                r"^\"?'(.+)'\"?$", r"\1", rendered_metadata_default
            )

        if rendered_inspector_default is not None:
            rendered_inspector_default = re.sub(
                r"^\((.+)\)$", r"\1", rendered_inspector_default
            )

            rendered_inspector_default = re.sub(
                r"^\"?'(.+)'\"?$", r"\1", rendered_inspector_default
            )

            rendered_inspector_default = rendered_inspector_default.strip()
        return rendered_inspector_default != rendered_metadata_default

    def emit_begin(self) -> None:
        self._exec("SET TRANSACTION READ WRITE")

    def emit_commit(self) -> None:
        self._exec("COMMIT")


@compiles(AddColumn, "oracle")
def visit_add_column(
    element: AddColumn, compiler: OracleDDLCompiler, **kw
) -> str:
    return "%s %s" % (
        alter_table(compiler, element.table_name, element.schema),
        add_column(compiler, element.column, **kw),
    )


@compiles(ColumnNullable, "oracle")
def visit_column_nullable(
    element: ColumnNullable, compiler: OracleDDLCompiler, **kw
) -> str:
    return "%s %s %s" % (
        alter_table(compiler, element.table_name, element.schema),
        alter_column(compiler, element.column_name),
        "NULL" if element.nullable else "NOT NULL",
    )


@compiles(ColumnType, "oracle")
def visit_column_type(
    element: ColumnType, compiler: OracleDDLCompiler, **kw
) -> str:
    return "%s %s %s" % (
        alter_table(compiler, element.table_name, element.schema),
        alter_column(compiler, element.column_name),
        "%s" % format_type(compiler, element.type_),
    )


@compiles(ColumnName, "oracle")
def visit_column_name(
    element: ColumnName, compiler: OracleDDLCompiler, **kw
) -> str:
    return "%s RENAME COLUMN %s TO %s" % (
        alter_table(compiler, element.table_name, element.schema),
        format_column_name(compiler, element.column_name),
        format_column_name(compiler, element.newname),
    )


@compiles(ColumnDefault, "oracle")
def visit_column_default(
    element: ColumnDefault, compiler: OracleDDLCompiler, **kw
) -> str:
    return "%s %s %s" % (
        alter_table(compiler, element.table_name, element.schema),
        alter_column(compiler, element.column_name),
        (
            "DEFAULT %s" % format_server_default(compiler, element.default)
            if element.default is not None
            else "DEFAULT NULL"
        ),
    )


@compiles(ColumnComment, "oracle")
def visit_column_comment(
    element: ColumnComment, compiler: OracleDDLCompiler, **kw
) -> str:
    ddl = "COMMENT ON COLUMN {table_name}.{column_name} IS {comment}"

    comment = compiler.sql_compiler.render_literal_value(
        (element.comment if element.comment is not None else ""),
        sqltypes.String(),
    )

    return ddl.format(
        table_name=element.table_name,
        column_name=element.column_name,
        comment=comment,
    )


@compiles(RenameTable, "oracle")
def visit_rename_table(
    element: RenameTable, compiler: OracleDDLCompiler, **kw
) -> str:
    return "%s RENAME TO %s" % (
        alter_table(compiler, element.table_name, element.schema),
        format_table_name(compiler, element.new_table_name, None),
    )


def alter_column(compiler: OracleDDLCompiler, name: str) -> str:
    return "MODIFY %s" % format_column_name(compiler, name)


def add_column(compiler: OracleDDLCompiler, column: Column[Any], **kw) -> str:
    return "ADD %s" % compiler.get_column_specification(column, **kw)


@compiles(IdentityColumnDefault, "oracle")
def visit_identity_column(
    element: IdentityColumnDefault, compiler: OracleDDLCompiler, **kw
):
    text = "%s %s " % (
        alter_table(compiler, element.table_name, element.schema),
        alter_column(compiler, element.column_name),
    )
    if element.default is None:
        # drop identity
        text += "DROP IDENTITY"
        return text
    else:
        text += compiler.visit_identity_column(element.default)
        return text