docview/cmake/WriteWindowsRuntimeManifest.cmake

# Script API: -DWORKER_EXECUTABLE=<absolute exe> -DRUNTIME_FILES=<absolute list>
# Include API: docview_write_windows_runtime_manifest(executable "${files}").
# This writer validates the package inventory, not the PE import table. The
# native dependency scanner is StageWindowsWorker.cmake.
cmake_minimum_required(VERSION 3.24)
include_guard(GLOBAL)

function(docview_runtime_file_info path kind out_name out_size)
    if(NOT IS_ABSOLUTE "${path}" OR NOT EXISTS "${path}" OR IS_DIRECTORY "${path}" OR IS_SYMLINK "${path}")
        message(FATAL_ERROR "Worker runtime requires an absolute regular file: ${path}")
    endif()
    get_filename_component(name "${path}" NAME)
    string(LENGTH "${name}" length)
    string(TOLOWER "${name}" folded)
    if(length GREATER 128 OR NOT name MATCHES "^[A-Za-z0-9][A-Za-z0-9._-]*$" OR
       name MATCHES "[.]$" OR folded MATCHES "^(con|prn|aux|nul|com[1-9]|lpt[1-9])([.]|$)")
        message(FATAL_ERROR "Invalid Windows runtime filename: ${name}")
    endif()
    if((kind STREQUAL "EXE" AND NOT folded MATCHES "[.]exe$") OR
       (kind STREQUAL "DLL" AND NOT folded MATCHES "[.]dll$"))
        message(FATAL_ERROR "Only the worker executable and DLLs may enter its runtime: ${name}")
    endif()
    file(SIZE "${path}" size)
    if(size LESS 2 OR size GREATER 268435456)
        message(FATAL_ERROR "Worker runtime file exceeds the 256 MiB limit or is empty: ${name}")
    endif()
    file(READ "${path}" signature LIMIT 2 HEX)
    if(NOT signature STREQUAL "4d5a")
        message(FATAL_ERROR "Worker runtime file has no MZ signature: ${name}")
    endif()
    set(${out_name} "${name}" PARENT_SCOPE)
    set(${out_size} "${size}" PARENT_SCOPE)
endfunction()

function(docview_write_windows_runtime_manifest executable files)
    docview_runtime_file_info("${executable}" EXE executable_name executable_size)
    file(REAL_PATH "${executable}" executable_real)
    get_filename_component(directory "${executable_real}" DIRECTORY)
    if(WIN32)
        string(TOLOWER "${directory}" directory)
    endif()
    list(LENGTH files count)
    if(count LESS 1 OR count GREATER 128)
        message(FATAL_ERROR "Worker runtime inventory must contain 1..128 files")
    endif()
    set(seen)
    set(total 0)
    set(has_executable FALSE)
    # Check every limit before hashing potentially large files or changing an
    # existing manifest. File order does not affect the serialized inventory.
    foreach(path IN LISTS files)
        get_filename_component(name "${path}" NAME)
        if(name STREQUAL executable_name)
            set(kind EXE)
        else()
            set(kind DLL)
        endif()
        docview_runtime_file_info("${path}" "${kind}" name size)
        file(REAL_PATH "${path}" real)
        get_filename_component(parent "${real}" DIRECTORY)
        if(WIN32)
            string(TOLOWER "${parent}" parent)
        endif()
        if(NOT parent STREQUAL directory)
            message(FATAL_ERROR "Manifest entries must already be beside the worker: ${name}")
        endif()
        string(TOLOWER "${name}" key)
        if(key IN_LIST seen)
            message(FATAL_ERROR "Case-insensitive duplicate worker runtime filename: ${name}")
        endif()
        list(APPEND seen "${key}")
        if(name STREQUAL executable_name)
            if(NOT real STREQUAL executable_real)
                message(FATAL_ERROR "Manifest executable does not match its worker")
            endif()
            set(has_executable TRUE)
        endif()
        math(EXPR total "${total} + ${size}")
        if(total GREATER 536870912)
            message(FATAL_ERROR "Worker runtime exceeds the 512 MiB aggregate limit")
        endif()
    endforeach()
    if(NOT has_executable)
        message(FATAL_ERROR "Worker runtime manifest must include its executable")
    endif()
    list(SORT files CASE INSENSITIVE)
    set(entries)
    foreach(path IN LISTS files)
        get_filename_component(name "${path}" NAME)
        file(SIZE "${path}" size)
        file(SHA256 "${path}" digest)
        string(TOLOWER "${digest}" digest)
        list(APPEND entries "    {\"path\":\"${name}\",\"sha256\":\"${digest}\",\"size\":${size}}")
    endforeach()
    list(JOIN entries ",\n" entries_json)
    set(json "{\n  \"schemaVersion\":1,\n  \"executable\":\"${executable_name}\",\n  \"files\":[\n${entries_json}\n  ]\n}\n")
    string(LENGTH "${json}" json_size)
    if(json_size GREATER 131072)
        message(FATAL_ERROR "Worker runtime manifest exceeds its 128 KiB limit")
    endif()
    set(output "${executable}.runtime.json")
    if(IS_SYMLINK "${output}" OR IS_DIRECTORY "${output}")
        message(FATAL_ERROR "Refusing a non-regular worker runtime manifest destination")
    endif()
    string(RANDOM LENGTH 24 ALPHABET 0123456789abcdef nonce)
    set(temporary "${output}.${nonce}.tmp")
    if(EXISTS "${temporary}" OR IS_SYMLINK "${temporary}")
        message(FATAL_ERROR "Worker runtime manifest temporary path already exists")
    endif()
    file(WRITE "${temporary}" "${json}")
    file(RENAME "${temporary}" "${output}" RESULT renamed)
    if(NOT renamed STREQUAL "0")
        file(REMOVE "${temporary}")
        message(FATAL_ERROR "Cannot atomically publish worker runtime manifest: ${renamed}")
    endif()
endfunction()

if(CMAKE_SCRIPT_MODE_FILE STREQUAL CMAKE_CURRENT_LIST_FILE)
    if(NOT DEFINED WORKER_EXECUTABLE OR NOT DEFINED RUNTIME_FILES)
        message(FATAL_ERROR "WORKER_EXECUTABLE and RUNTIME_FILES are required")
    endif()
    docview_write_windows_runtime_manifest("${WORKER_EXECUTABLE}" "${RUNTIME_FILES}")
endif()