Source code for grass.grassdb.data

"""
Manipulate data in mapsets in GRASS Spatial Database

SPDX-FileCopyrightText: 2020 GRASS Development Team
SPDX-License-Identifier: GPL-2.0-or-later

.. sectionauthor:: Vaclav Petras <wenzeslaus gmail com>
"""

import grass.script as gs
from grass.tools import Tools, ToolError




def map_exists(name, element, mapset=None, env=None) -> bool:
    """Check is map is present in the mapset given in the environment

    :param name: Name of the map
    :param element: Data type ('raster', 'raster_3d', and 'vector')
    :param env: Environment created by function grass.script.create_environment
    :param mapset: Mapset name, "." for current mapset only,
                   None for all mapsets in the search path
    """
    # change type to element used by find file
    if element == "raster":
        element = "cell"
    elif element == "raster_3d":
        element = "grid3"
    # g.findfile returns non-zero when file was not found
    # se we ignore return code and just focus on stdout
    process = gs.start_command(
        "g.findfile",
        flags="n",
        element=element,
        file=name,
        mapset=mapset,
        stdout=gs.PIPE,
        stderr=gs.PIPE,
        env=env,
    )
    output, unused_errors = process.communicate()
    info = gs.parse_key_val(output, sep="=")
    # file is the key questioned in grass.script.core find_file()
    # return code should be equivalent to checking the output
    return bool(info["file"])





def stds_exists(name, element, mapset, env=None) -> bool:
    """Check if a space time dataset (STDS) is present in the temporal database.

    :param name: Name of the space time dataset
    :param element: STDS type ('strds', 'stvds', 'str3ds')
    :param mapset: Mapset name where the dataset is located
    :param env: Environment created by function grass.script.create_environment
    """
    # The where clause goes to SQL as it is, and a quote inside a SQL string
    # literal has to be written twice to not end the literal early.
    escaped_name = name.replace("'", "''")
    tools = Tools(env=env)
    try:
        output = tools.t_list(
            type=element,
            columns="name",
            where=f"name='{escaped_name}'",
            mapset=mapset,
            format="json",
            quiet=True,
        )
        return bool(output.json)
    except ToolError:
        return False