Refactor DownloadURL.sh

Auto-detects and verifies all kinds of hashes, not only SHA1.
Hash verification is now an autonomous function.
If the file is found at the destination, skip redownloading it if the
hash is OK.
Runs on POSIX sh, not requiring bash.
Retain compatibility with previous version.

Change-Id: I9930336030aa776f49dc460fe766f3e831700255
Reviewed-by: Tony Sarajärvi <[email protected]>
(cherry picked from commit c0fce7a)
Reviewed-by: Heikki Halmet <[email protected]>

Author: jimis

coin/provisioning/common/unix/DownloadURL.sh

@@ -1,8 +1,8 @@
-#!/usr/bin/env bash
+#!/bin/sh
 
 #############################################################################
 ##
-## Copyright (C) 2017 The Qt Company Ltd.
+## Copyright (C) 2019 The Qt Company Ltd.
 ## Contact: http://www.qt.io/licensing/
 ##
 ## This file is part of the provisioning scripts of the Qt Toolkit.
@@ -33,31 +33,69 @@
 ##
 #############################################################################
 
+
 # A helper script used for downloading a file from a URL or an alternative
-# URL. Also the SHA1 is checked for the file. Target filename should also
-# be given.
-#
-# If called directly from another script, it will exit the parent script
-# as well, if not called in its own subshell with parentheses.
+# URL. Also the SHA is checked for the file (SHA algorithm is autodetected
+# based on the SHA length). Target filename should also be given.
+
+############################ BOILERPLATE ###############################
+command -v sha1sum >/dev/null   ||  alias   sha1sum='shasum -a 1'
+command -v sha256sum >/dev/null ||  alias sha256sum='shasum -a 256'
+command -v sha384sum >/dev/null ||  alias sha384sum='shasum -a 384'
+command -v sha512sum >/dev/null ||  alias sha512sum='shasum -a 512'
+########################################################################
+
+
+VerifyHash () {
+    file=$1
+    expectedHash=$2
+
+    if [ ! -f "$file" ]
+    then  return 2              # file does not exist
+    fi
 
-set -ex
 
-function DownloadURL {
+    hashLength="$(echo "$expectedHash" | wc -c | sed 's/ *//g')"
+    # Use backticks because of bug with bash-3 (default on macOS),
+    # caused when there are unbalanced parentheses inside $()
+    # shellcheck disable=SC2006
+    hash=`case "$hashLength" in
+            41)  sha1sum    "$file"  ;;
+            65)  sha256sum  "$file"  ;;
+            97)  sha384sum  "$file"  ;;
+            129) sha512sum  "$file"  ;;
+            *) echo "FATAL! Unknown hash length:  $hashLength" 1>&2  &&  exit 1  ;;
+        esac | cut -d ' ' -f 1`
+
+    if [ ! "$expectedHash" = "$hash" ]
+    then
+        echo "FAIL! wrong file hash:  $file  $hash"  1>&2
+        return 1
+    fi
+    echo "OK verified integrity of:  $file"
+}
+
+# Check if file already exists and is good, otherwise download it
+DownloadURL () {
     url=$1
-    url_alt=$2
-    expectedSha1=$3
+    url2=$2
+    expectedHash=$3
     targetFile=$4
 
-    echo "Downloading from primary URL '$url'"
-    curl --fail -L --retry 5 --retry-delay 5 -o "$targetFile" "$url" ||  {
-        echo "Failed to download '$url' multiple times"
-        echo "Downloading from alternative URL '$url_alt'"
-        curl --fail -L --retry 5 --retry-delay 5 -o "$targetFile" "$url_alt" || { echo 'Failed to download even from alternative url'; exit 1; }
-    }
-
-    echo "Checking SHA1 on PKG '$targetFile'"
-    echo "$expectedSha1 *$targetFile" > "$targetFile.sha1"
-    sha1sum --check "$targetFile.sha1"
-    rm -f "$targetFile.sha1"
+    if VerifyHash "$targetFile" "$expectedHash"
+    then
+        echo "Skipping download, found and validated existing file:  $targetFile"
+    else
+        echo "Downloading from primary URL:  $url"
+        if  ! curl --fail -L --retry 5 --retry-delay 5 -o "$targetFile" "$url"
+        then
+            echo "FAIL! to download, trying alternative URL:  $url2"  1>&2
+            if  ! curl --fail -L --retry 5 --retry-delay 5 -o "$targetFile" "$url2"
+            then
+                echo 'FAIL! to download even from alternative url'  1>&2
+                return 1
+            fi
+        fi
+        VerifyHash "$targetFile" "$expectedHash"
+    fi
 }
-