cmake: update ocv_download

- more aggressive cache for files under CMAKE_BINARY_CACHE
  * don't re-read files MD5
  * don't repack archives
- add support for ENV{OPENCV_DOWNLOAD_PATH}
- added ID parameter as project/group identifier
- non-flat .cache directory (based on ID)
- download message prefix based on ID
- more detailed logging via ocv_download_log() macro
- force .gitignore file for .cache folder (with '*' pattern)

.gitignore

@@ -3,7 +3,6 @@
 *.user
 *~
 .*.swp
-.cache
 .DS_Store
 .sw[a-z]
 Thumbs.db

3rdparty/ffmpeg/ffmpeg.cmake

@@ -25,6 +25,7 @@ function(download_win_ffmpeg script_var)
                  "${OPENCV_FFMPEG_URL}"
                  "https://raw.githubusercontent.com/opencv/opencv_3rdparty/${FFMPEG_BINARIES_COMMIT}/ffmpeg/"
                DESTINATION_DIR ${FFMPEG_DOWNLOAD_DIR}
+               ID FFMPEG
                RELATIVE_URL
                STATUS res)
     if(NOT res)

3rdparty/ippicv/ippicv.cmake

@@ -31,6 +31,7 @@ function(download_ippicv root_var)
                  "$ENV{OPENCV_IPPICV_URL}"
                  "https://raw.githubusercontent.com/opencv/opencv_3rdparty/${IPPICV_COMMIT}/ippicv/"
                DESTINATION_DIR "${THE_ROOT}"
+               ID IPPICV
                STATUS res
                UNPACK RELATIVE_URL)
 

3rdparty/tbb/CMakeLists.txt

@@ -21,6 +21,7 @@ ocv_download(FILENAME ${tbb_filename}
                "$ENV{OPENCV_TBB_URL}"
                "https://github.com/01org/tbb/archive/"
              DESTINATION_DIR ${tbb_src_dir}
+             ID TBB
              STATUS res
              UNPACK RELATIVE_URL)
 if(NOT res)

cmake/OpenCVDownload.cmake

@@ -1,11 +1,12 @@
 #
 #  Download and optionally unpack a file
 #
-#  ocv_download(FILENAME p HASH h URL u1 [u2 ...] DESTINATION_DIR d [STATUS s] [UNPACK] [RELATIVE])
+#  ocv_download(FILENAME p HASH h URL u1 [u2 ...] DESTINATION_DIR d [ID id] [STATUS s] [UNPACK] [RELATIVE_URL])
 #    FILENAME - filename
 #    HASH - MD5 hash
 #    URL - full download url (first nonempty value will be chosen)
 #    DESTINATION_DIR - file will be copied to this directory
+#    ID     - identifier for project/group of downloaded files
 #    STATUS - passed variable will be updated in parent scope,
 #             function will not fail the build in case of download problem if this option is provided,
 #             but will fail in case when other operations (copy, remove, etc.) failed
@@ -13,28 +14,76 @@
 #    RELATIVE_URL - if set, then URL is treated as a base, and FILENAME will be appended to it
 #  Note: uses OPENCV_DOWNLOAD_PATH folder as cache, default is <opencv>/.cache
 
-set(OPENCV_DOWNLOAD_PATH "${OpenCV_SOURCE_DIR}/.cache" CACHE PATH "Cache directory for downloaded files")
+set(HELP_OPENCV_DOWNLOAD_PATH "Cache directory for downloaded files")
+if(DEFINED ENV{OPENCV_DOWNLOAD_PATH})
+  set(OPENCV_DOWNLOAD_PATH "$ENV{OPENCV_DOWNLOAD_PATH}" CACHE PATH "${HELP_OPENCV_DOWNLOAD_PATH}")
+endif()
+set(OPENCV_DOWNLOAD_PATH "${OpenCV_SOURCE_DIR}/.cache" CACHE PATH "${HELP_OPENCV_DOWNLOAD_PATH}")
 set(OPENCV_DOWNLOAD_LOG "${OpenCV_BINARY_DIR}/CMakeDownloadLog.txt")
 
 # Init download cache directory and log file
 if(NOT EXISTS "${OPENCV_DOWNLOAD_PATH}")
   file(MAKE_DIRECTORY ${OPENCV_DOWNLOAD_PATH})
 endif()
+if(NOT EXISTS "${OPENCV_DOWNLOAD_PATH}/.gitignore")
+  file(WRITE "${OPENCV_DOWNLOAD_PATH}/.gitignore" "*\n")
+endif()
 file(WRITE "${OPENCV_DOWNLOAD_LOG}" "use_cache \"${OPENCV_DOWNLOAD_PATH}\"\n")
 
 
 function(ocv_download)
-  cmake_parse_arguments(DL "UNPACK;RELATIVE_URL" "FILENAME;HASH;DESTINATION_DIR;STATUS" "URL" ${ARGN})
+  cmake_parse_arguments(DL "UNPACK;RELATIVE_URL" "FILENAME;HASH;DESTINATION_DIR;ID;STATUS" "URL" ${ARGN})
 
-  ocv_assert(DEFINED DL_FILENAME)
+  macro(ocv_download_log)
-  ocv_assert(DEFINED DL_HASH)
+    file(APPEND "${OPENCV_DOWNLOAD_LOG}" "${ARGN}\n")
-  ocv_assert(DEFINED DL_URL)
+  endmacro()
-  ocv_assert(DEFINED DL_DESTINATION_DIR)
+
+  ocv_assert(DL_FILENAME)
+  ocv_assert(DL_HASH)
+  ocv_assert(DL_URL)
+  ocv_assert(DL_DESTINATION_DIR)
+  if((NOT " ${DL_UNPARSED_ARGUMENTS}" STREQUAL " ")
+    OR DL_FILENAME STREQUAL ""
+    OR DL_HASH STREQUAL ""
+    OR DL_URL STREQUAL ""
+    OR DL_DESTINATION_DIR STREQUAL ""
+  )
+    set(msg_level FATAL_ERROR)
+    if(DEFINED DL_STATUS)
+      set(${DL_STATUS} FALSE PARENT_SCOPE)
+      set(msg_level WARNING)
+    endif()
+    message(${msg_level} "ERROR: ocv_download() unsupported arguments: ${ARGV}")
+    return()
+  endif()
 
   if(DEFINED DL_STATUS)
     set(${DL_STATUS} TRUE PARENT_SCOPE)
   endif()
 
+  # Check CMake cache for already processed tasks
+  string(FIND "${DL_DESTINATION_DIR}" "${CMAKE_BINARY_DIR}" DL_BINARY_PATH_POS)
+  if(DL_BINARY_PATH_POS EQUAL 0)
+    set(__file_id "${DL_DESTINATION_DIR}/${DL_FILENAME}")
+    file(RELATIVE_PATH __file_id "${CMAKE_BINARY_DIR}" "${__file_id}")
+    string(REGEX REPLACE "[^a-zA-Z0-9_]" "_" __file_id "${__file_id}")
+    if(DL_ID)
+      string(TOUPPER ${DL_ID} __id)
+      string(REGEX REPLACE "[^a-zA-Z0-9_]" "_" __id "${__id}")
+      set(OCV_DOWNLOAD_HASH_NAME "OCV_DOWNLOAD_${__id}_HASH_${__file_id}")
+    else()
+      set(OCV_DOWNLOAD_HASH_NAME "OCV_DOWNLOAD_HASH_${__file_id}")
+    endif()
+    if(" ${${OCV_DOWNLOAD_HASH_NAME}}" STREQUAL " ${DL_HASH}")
+      ocv_download_log("#match_hash_in_cmake_cache \"${OCV_DOWNLOAD_HASH_NAME}\"")
+      return()
+    endif()
+    unset("${OCV_DOWNLOAD_HASH_NAME}" CACHE)
+  else()
+    set(OCV_DOWNLOAD_HASH_NAME "")
+    #message(WARNING "Download destination is not in CMAKE_BINARY_DIR=${CMAKE_BINARY_DIR}: ${DL_DESTINATION_DIR}")
+  endif()
+
   # Select first non-empty url
   foreach(url ${DL_URL})
     if(url)
@@ -54,58 +103,85 @@ function(ocv_download)
   endif()
 
   # Log all calls to file
-  file(APPEND "${OPENCV_DOWNLOAD_LOG}" "do_${mode} \"${DL_FILENAME}\" \"${DL_HASH}\" \"${DL_URL}\" \"${DL_DESTINATION_DIR}\"\n")
+  ocv_download_log("do_${mode} \"${DL_FILENAME}\" \"${DL_HASH}\" \"${DL_URL}\" \"${DL_DESTINATION_DIR}\"")
   # ... and to console
-  message(STATUS "Download: ${DL_FILENAME}")
+  set(__msg_prefix "")
+  if(DL_ID)
+    set(__msg_prefix "${DL_ID}: ")
+  endif()
+  message(STATUS "${__msg_prefix}Download: ${DL_FILENAME}")
 
   # Copy mode: check if copy destination exists and is correct
   if(NOT DL_UNPACK)
     set(COPY_DESTINATION "${DL_DESTINATION_DIR}/${DL_FILENAME}")
     if(EXISTS "${COPY_DESTINATION}")
+      ocv_download_log("#check_md5 \"${COPY_DESTINATION}\"")
       file(MD5 "${COPY_DESTINATION}" target_md5)
       if(target_md5 STREQUAL DL_HASH)
+        ocv_download_log("#match_md5 \"${COPY_DESTINATION}\" \"${target_md5}\"")
+        if(OCV_DOWNLOAD_HASH_NAME)
+          set(${OCV_DOWNLOAD_HASH_NAME} "${DL_HASH}" CACHE INTERNAL "")
+        endif()
         return()
       endif()
+      ocv_download_log("#mismatch_md5 \"${COPY_DESTINATION}\" \"${target_md5}\"")
+    else()
+      ocv_download_log("#missing \"${COPY_DESTINATION}\"")
     endif()
   endif()
 
   # Check cache first
+  if(DL_ID)
+    string(TOLOWER "${DL_ID}" __id)
+    string(REGEX REPLACE "[^a-zA-Z0-9_/ ]" "_" __id "${__id}")
+    set(CACHE_CANDIDATE "${OPENCV_DOWNLOAD_PATH}/${__id}/${DL_HASH}-${DL_FILENAME}")
+  else()
     set(CACHE_CANDIDATE "${OPENCV_DOWNLOAD_PATH}/${DL_HASH}-${DL_FILENAME}")
+  endif()
   if(EXISTS "${CACHE_CANDIDATE}")
+    ocv_download_log("#check_md5 \"${CACHE_CANDIDATE}\"")
     file(MD5 "${CACHE_CANDIDATE}" target_md5)
     if(NOT target_md5 STREQUAL DL_HASH)
+      ocv_download_log("#mismatch_md5 \"${CACHE_CANDIDATE}\" \"${target_md5}\"")
+      ocv_download_log("#delete \"${CACHE_CANDIDATE}\"")
       file(REMOVE ${CACHE_CANDIDATE})
     endif()
   endif()
 
   # Download
   if(NOT EXISTS "${CACHE_CANDIDATE}")
+    ocv_download_log("#cmake_download \"${CACHE_CANDIDATE}\" \"${DL_URL}\"")
     file(DOWNLOAD "${DL_URL}" "${CACHE_CANDIDATE}"
          INACTIVITY_TIMEOUT 60
          TIMEOUT 600
          STATUS status
-         LOG log)
+         LOG __log)
-    string(REPLACE "\n" "\n# " log "# ${log}")
+    string(LENGTH "${__log}" __log_length)
-    file(APPEND "${OPENCV_DOWNLOAD_LOG}" "${log}\n\n")
+    if(__log_length LESS 65536)
+      string(REPLACE "\n" "\n# " __log "${__log}")
+      ocv_download_log("# ${__log}\n")
+    endif()
     if(NOT status EQUAL 0)
       set(msg_level FATAL_ERROR)
       if(DEFINED DL_STATUS)
         set(${DL_STATUS} FALSE PARENT_SCOPE)
         set(msg_level WARNING)
       endif()
-      message(${msg_level} "Download failed: ${status}")
+      message(${msg_level} "${__msg_prefix}Download failed: ${status}")
       return()
     endif()
 
     # Don't remove this code, because EXPECTED_MD5 parameter doesn't fail "file(DOWNLOAD)" step on wrong hash
+    ocv_download_log("#check_md5 \"${CACHE_CANDIDATE}\"")
     file(MD5 "${CACHE_CANDIDATE}" target_md5)
     if(NOT target_md5 STREQUAL DL_HASH)
+      ocv_download_log("#mismatch_md5 \"${CACHE_CANDIDATE}\" \"${target_md5}\"")
       set(msg_level FATAL_ERROR)
       if(DEFINED DL_STATUS)
         set(${DL_STATUS} FALSE PARENT_SCOPE)
         set(msg_level WARNING)
       endif()
-      message(${msg_level} "Hash mismatch: ${target_md5}")
+      message(${msg_level} "${__msg_prefix}Hash mismatch: ${target_md5}")
       return()
     endif()
   endif()
@@ -113,21 +189,28 @@ function(ocv_download)
   # Unpack or copy
   if(DL_UNPACK)
     if(EXISTS "${DL_DESTINATION_DIR}")
+      ocv_download_log("#remove_unpack \"${DL_DESTINATION_DIR}\"")
       file(REMOVE_RECURSE "${DL_DESTINATION_DIR}")
     endif()
+    ocv_download_log("#mkdir \"${DL_DESTINATION_DIR}\"")
     file(MAKE_DIRECTORY "${DL_DESTINATION_DIR}")
+    ocv_download_log("#unpack \"${DL_DESTINATION_DIR}\" \"${CACHE_CANDIDATE}\"")
     execute_process(COMMAND "${CMAKE_COMMAND}" -E tar xz "${CACHE_CANDIDATE}"
                     WORKING_DIRECTORY "${DL_DESTINATION_DIR}"
                     RESULT_VARIABLE res)
     if(NOT res EQUAL 0)
-      message(FATAL_ERROR "Unpack failed: ${res}")
+      message(FATAL_ERROR "${__msg_prefix}Unpack failed: ${res}")
     endif()
   else()
+    ocv_download_log("#copy \"${COPY_DESTINATION}\" \"${CACHE_CANDIDATE}\"")
     execute_process(COMMAND ${CMAKE_COMMAND} -E copy_if_different "${CACHE_CANDIDATE}" "${COPY_DESTINATION}"
                     RESULT_VARIABLE res)
     if(NOT res EQUAL 0)
-      message(FATAL_ERROR "Copy failed: ${res}")
+      message(FATAL_ERROR "${__msg_prefix}Copy failed: ${res}")
     endif()
   endif()
 
+  if(OCV_DOWNLOAD_HASH_NAME)
+    set(${OCV_DOWNLOAD_HASH_NAME} "${DL_HASH}" CACHE INTERNAL "")
+  endif()
 endfunction()