vcpkg/scripts/cmake/vcpkg_download_distfile.cmake

#[===[.md:
# vcpkg_download_distfile

Download and cache a file needed for this port.

This helper should always be used instead of CMake's built-in `file(DOWNLOAD)` command.

## Usage
```cmake
vcpkg_download_distfile(
    <OUT_VARIABLE>
    URLS <http://mainUrl> <http://mirror1>...
    FILENAME <output.zip>
    SHA512 <5981de...>
)
```
## Parameters
### OUT_VARIABLE
This variable will be set to the full path to the downloaded file. This can then immediately be passed in to [`vcpkg_extract_source_archive`](vcpkg_extract_source_archive.md) for sources.

### URLS
A list of URLs to be consulted. They will be tried in order until one of the downloaded files successfully matches the SHA512 given.

### FILENAME
The local name for the file. Files are shared between ports, so the file may need to be renamed to make it clearly attributed to this port and avoid conflicts.

### SHA512
The expected hash for the file.

If this doesn't match the downloaded version, the build will be terminated with a message describing the mismatch.

### QUIET
Suppress output on cache hit

### SKIP_SHA512
Skip SHA512 hash check for file.

This switch is only valid when building with the `--head` command line flag.

### HEADERS
A list of headers to append to the download request. This can be used for authentication during a download.

Headers should be specified as "<header-name>: <header-value>".

## Notes
The helper [`vcpkg_from_github`](vcpkg_from_github.md) should be used for downloading from GitHub projects.

## Examples

* [apr](https://github.com/Microsoft/vcpkg/blob/master/ports/apr/portfile.cmake)
* [fontconfig](https://github.com/Microsoft/vcpkg/blob/master/ports/fontconfig/portfile.cmake)
* [freetype](https://github.com/Microsoft/vcpkg/blob/master/ports/freetype/portfile.cmake)
#]===]

include(vcpkg_execute_in_download_mode)

function(vcpkg_download_distfile VAR)
    set(options SKIP_SHA512 SILENT_EXIT QUIET)
    set(oneValueArgs FILENAME SHA512)
    set(multipleValuesArgs URLS HEADERS)
    # parse parameters such that semicolons in options arguments to COMMAND don't get erased
    cmake_parse_arguments(PARSE_ARGV 1 vcpkg_download_distfile "${options}" "${oneValueArgs}" "${multipleValuesArgs}")

    if(NOT DEFINED vcpkg_download_distfile_URLS)
        message(FATAL_ERROR "vcpkg_download_distfile requires a URLS argument.")
    endif()
    if(NOT DEFINED vcpkg_download_distfile_FILENAME)
        message(FATAL_ERROR "vcpkg_download_distfile requires a FILENAME argument.")
    endif()
    if(NOT _VCPKG_INTERNAL_NO_HASH_CHECK)
        if(NOT vcpkg_download_distfile_SKIP_SHA512 AND NOT DEFINED vcpkg_download_distfile_SHA512)
            message(FATAL_ERROR "vcpkg_download_distfile requires a SHA512 argument. If you do not know the SHA512, add it as 'SHA512 0' and re-run this command.")
        endif()
        if(vcpkg_download_distfile_SKIP_SHA512 AND DEFINED vcpkg_download_distfile_SHA512)
            message(FATAL_ERROR "vcpkg_download_distfile must not be passed both SHA512 and SKIP_SHA512.")
        endif()
    endif()

    set(downloaded_file_path ${DOWNLOADS}/${vcpkg_download_distfile_FILENAME})
    set(download_file_path_part "${DOWNLOADS}/temp/${vcpkg_download_distfile_FILENAME}")

    # Works around issue #3399
    if(IS_DIRECTORY "${DOWNLOADS}/temp")
        # Delete "temp0" directory created by the old version of vcpkg
        file(REMOVE_RECURSE "${DOWNLOADS}/temp0")

        file(GLOB temp_files "${DOWNLOADS}/temp")
        file(REMOVE_RECURSE ${temp_files})
    else()
      file(MAKE_DIRECTORY "${DOWNLOADS}/temp")
    endif()

    function(test_hash FILE_PATH FILE_KIND CUSTOM_ERROR_ADVICE)
        if(_VCPKG_INTERNAL_NO_HASH_CHECK)
            # When using the internal hash skip, do not output an explicit message.
            return()
        endif()
        if(vcpkg_download_distfile_SKIP_SHA512)
            message(STATUS "Skipping hash check for ${FILE_PATH}.")
            return()
        endif()

        file(SHA512 ${FILE_PATH} FILE_HASH)
        if(NOT FILE_HASH STREQUAL vcpkg_download_distfile_SHA512)
            message(FATAL_ERROR
                "\nFile does not have expected hash:\n"
                "        File path: [ ${FILE_PATH} ]\n"
                "    Expected hash: [ ${vcpkg_download_distfile_SHA512} ]\n"
                "      Actual hash: [ ${FILE_HASH} ]\n"
                "${CUSTOM_ERROR_ADVICE}\n")
        endif()
    endfunction()

    if(EXISTS "${downloaded_file_path}")
        if(NOT vcpkg_download_distfile_QUIET)
            message(STATUS "Using cached ${downloaded_file_path}")
        endif()
        test_hash("${downloaded_file_path}" "cached file" "Please delete the file and retry if this file should be downloaded again.")
    else()
        if(_VCPKG_NO_DOWNLOADS)
            message(FATAL_ERROR "Downloads are disabled, but '${downloaded_file_path}' does not exist.")
        endif()

        # Tries to download the file.
        list(GET vcpkg_download_distfile_URLS 0 SAMPLE_URL)
        if(_VCPKG_DOWNLOAD_TOOL STREQUAL "ARIA2" AND NOT SAMPLE_URL MATCHES "aria2")
            vcpkg_find_acquire_program("ARIA2")
            message(STATUS "Downloading ${vcpkg_download_distfile_FILENAME}...")
            if(vcpkg_download_distfile_HEADERS)
                foreach(header ${vcpkg_download_distfile_HEADERS})
                    list(APPEND request_headers "--header=${header}")
                endforeach()
            endif()
            vcpkg_execute_in_download_mode(
                COMMAND ${ARIA2} ${vcpkg_download_distfile_URLS}
                -o temp/${vcpkg_download_distfile_FILENAME}
                -l download-${vcpkg_download_distfile_FILENAME}-detailed.log
                ${request_headers}
                OUTPUT_FILE download-${vcpkg_download_distfile_FILENAME}-out.log
                ERROR_FILE download-${vcpkg_download_distfile_FILENAME}-err.log
                RESULT_VARIABLE error_code
                WORKING_DIRECTORY ${DOWNLOADS}
            )
            if (NOT "${error_code}" STREQUAL "0")
                message(STATUS
                    "Downloading ${vcpkg_download_distfile_FILENAME}... Failed.\n"
                    "    Exit Code: ${error_code}\n"
                    "    See logs for more information:\n"
                    "        ${DOWNLOADS}/download-${vcpkg_download_distfile_FILENAME}-out.log\n"
                    "        ${DOWNLOADS}/download-${vcpkg_download_distfile_FILENAME}-err.log\n"
                    "        ${DOWNLOADS}/download-${vcpkg_download_distfile_FILENAME}-detailed.log\n"
                )
                set(download_success 0)
            else()
                file(REMOVE
                    ${DOWNLOADS}/download-${vcpkg_download_distfile_FILENAME}-out.log
                    ${DOWNLOADS}/download-${vcpkg_download_distfile_FILENAME}-err.log
                    ${DOWNLOADS}/download-${vcpkg_download_distfile_FILENAME}-detailed.log
                )
                set(download_success 1)
            endif()
        else()
            foreach(url IN LISTS vcpkg_download_distfile_URLS)
                message(STATUS "Downloading ${url}...")
                if(vcpkg_download_distfile_HEADERS)
                    foreach(header ${vcpkg_download_distfile_HEADERS})
                        list(APPEND request_headers HTTPHEADER ${header})
                    endforeach()
                endif()
                file(DOWNLOAD "${url}" "${download_file_path_part}" STATUS download_status ${request_headers})
                list(GET download_status 0 status_code)
                if (NOT "${status_code}" STREQUAL "0")
                    message(STATUS "Downloading ${url}... Failed. Status: ${download_status}")
                    set(download_success 0)
                else()
                    set(download_success 1)
                    break()
                endif()
            endforeach(url)
        endif()

        if (NOT vcpkg_download_distfile_SILENT_EXIT)
            if (NOT download_success)
                message(FATAL_ERROR
                "    \n"
                "    Failed to download file.\n"
                "    If you use a proxy, please set the HTTPS_PROXY and HTTP_PROXY environment\n"
                "    variables to \"https://user:password@your-proxy-ip-address:port/\".\n"
                "    Otherwise, please submit an issue at https://github.com/Microsoft/vcpkg/issues\n")
            else()
                test_hash("${download_file_path_part}" "downloaded file" "The file may have been corrupted in transit. This can be caused by proxies. If you use a proxy, please set the HTTPS_PROXY and HTTP_PROXY environment variables to \"https://user:password@your-proxy-ip-address:port/\".\n")
                get_filename_component(downloaded_file_dir "${downloaded_file_path}" DIRECTORY)
                file(MAKE_DIRECTORY "${downloaded_file_dir}")
                file(RENAME ${download_file_path_part} ${downloaded_file_path})
            endif()
        else()
            if (NOT download_success)
                message(WARNING
                "    \n"
                "    Failed to download file.\n")
            else()
                test_hash("${download_file_path_part}" "downloaded file" "The file may have been corrupted in transit. This can be caused by proxies. If you use a proxy, please set the HTTPS_PROXY and HTTP_PROXY environment variables to \"https://user:password@your-proxy-ip-address:port/\".\n")
                get_filename_component(downloaded_file_dir "${downloaded_file_path}" DIRECTORY)
                file(MAKE_DIRECTORY "${downloaded_file_dir}")
                file(RENAME ${download_file_path_part} ${downloaded_file_path})
            endif()
        endif()
    endif()
    set(${VAR} ${downloaded_file_path} PARENT_SCOPE)
endfunction()