cpp/cmake/DependencySource.cmake

#[[
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regarding copyright ownership.  The ASF licenses this file
to you under the Apache License, Version 2.0 (the
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    https://www.apache.org/licenses/LICENSE-2.0

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]]

include_guard(GLOBAL)

set(TSFILE_DEPENDENCY_CACHE "${CMAKE_BINARY_DIR}/dependency-cache"
        CACHE PATH
        "Directory containing downloaded third-party source archives")
set(TSFILE_DEPENDENCY_OFFLINE OFF
        CACHE BOOL
        "Disallow network downloads and require cached dependency archives")

set(TSFILE_DEPENDENCY_SOURCE "AUTO"
        CACHE STRING
        "Dependency source policy: AUTO, SYSTEM, or BUNDLED")
set_property(CACHE TSFILE_DEPENDENCY_SOURCE
        PROPERTY STRINGS AUTO SYSTEM BUNDLED)

string(TOUPPER "${TSFILE_DEPENDENCY_SOURCE}"
        _TSFILE_NORMALIZED_DEPENDENCY_SOURCE)
set(TSFILE_DEPENDENCY_SOURCE
        "${_TSFILE_NORMALIZED_DEPENDENCY_SOURCE}"
        CACHE STRING
        "Dependency source policy: AUTO, SYSTEM, or BUNDLED"
        FORCE)
unset(_TSFILE_NORMALIZED_DEPENDENCY_SOURCE)

set(_TSFILE_SUPPORTED_DEPENDENCY_SOURCES AUTO SYSTEM BUNDLED)
list(FIND _TSFILE_SUPPORTED_DEPENDENCY_SOURCES
        "${TSFILE_DEPENDENCY_SOURCE}"
        _TSFILE_DEPENDENCY_SOURCE_INDEX)
if (_TSFILE_DEPENDENCY_SOURCE_INDEX EQUAL -1)
    message(FATAL_ERROR
            "Invalid TSFILE_DEPENDENCY_SOURCE='${TSFILE_DEPENDENCY_SOURCE}'. "
            "Expected one of: AUTO, SYSTEM, BUNDLED.")
endif ()
unset(_TSFILE_DEPENDENCY_SOURCE_INDEX)
unset(_TSFILE_SUPPORTED_DEPENDENCY_SOURCES)

message(STATUS
        "TsFile dependency source policy: ${TSFILE_DEPENDENCY_SOURCE}")

# Resolve the source for one dependency after its migration has probed for a
# compatible system package. SYSTEM_FOUND must be a boolean value, not the name
# of a CMake variable. The selected source is returned as SYSTEM or BUNDLED.
function(tsfile_resolve_dependency_source DEPENDENCY SYSTEM_FOUND OUTPUT_VARIABLE)
    if (NOT ARGC EQUAL 3)
        message(FATAL_ERROR
                "tsfile_resolve_dependency_source expects: "
                "DEPENDENCY SYSTEM_FOUND OUTPUT_VARIABLE")
    endif ()
    if ("${DEPENDENCY}" STREQUAL "")
        message(FATAL_ERROR "Dependency name must not be empty.")
    endif ()
    if ("${OUTPUT_VARIABLE}" STREQUAL "")
        message(FATAL_ERROR
                "Output variable must not be empty for dependency ${DEPENDENCY}.")
    endif ()

    if (TSFILE_DEPENDENCY_SOURCE STREQUAL "BUNDLED")
        set(_TSFILE_SELECTED_SOURCE BUNDLED)
    elseif (SYSTEM_FOUND)
        set(_TSFILE_SELECTED_SOURCE SYSTEM)
    elseif (TSFILE_DEPENDENCY_SOURCE STREQUAL "SYSTEM")
        message(FATAL_ERROR
                "TSFILE_DEPENDENCY_SOURCE=SYSTEM requires a compatible "
                "system ${DEPENDENCY} package, but none was found.")
    else ()
        set(_TSFILE_SELECTED_SOURCE BUNDLED)
    endif ()

    message(STATUS
            "TsFile dependency ${DEPENDENCY}: ${_TSFILE_SELECTED_SOURCE}")
    set(${OUTPUT_VARIABLE} "${_TSFILE_SELECTED_SOURCE}" PARENT_SCOPE)
endfunction()