RFR: Add support for offline and local builds

[Erik Helin]

On Tue, 5 Nov 2019 15:34:44 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

> On Tue, 5 Nov 2019 13:15:24 GMT, Erik Helin <ehelin at openjdk.org> wrote:
> 
>> Hi all,
>> 
>> this patch adds much improved support for both _offline_ and _local_ builds. We are currently downloading both JDK and Gradle distributions for the most common platforms (GNU/Linux x64, macOS x64 and Windows x64), but this scheme does not scale to multiple other operating systems and/or CPU architectures. I have therefore extended the `images` plugin to support a `local` image which uses the JDK that is currently executing Gradle for producing the jlinked image.
>> 
>> I also added support for fully offline builds for those want to supply both a JDK and Gradle themselves and ensure that the build does not download anything.
>> 
>> Thanks,
>> Erik
>> 
>> ## Testing
>> - Tested multiple variants of builds, including local, offline and default builds
>> 
>> ----------------
>> 
>> Commits:
>>  - 66a6b56b: Added support for offline and local builds
>> 
>> Changes: https://git.openjdk.java.net/skara/pull/237/files
>>  Webrev: https://webrevs.openjdk.java.net/skara/237/webrev.00
>>   Stats: 300 lines in 10 files changed: 207 ins; 22 del; 71 mod
>>   Patch: https://git.openjdk.java.net/skara/pull/237.diff
>>   Fetch: git fetch https://git.openjdk.java.net/skara pull/237/head:pull/237
> 
> build.gradle line 125:
> 
>> 124: def getCPU() {
>> 125:     def cpu = System.getProperty('os.arch').toLowerCase()
>> 126:     if (cpu.startsWith('amd64')) {
> 
> I think this is x86_64 on Mac for 64 bit platforms

Fixed, also added a check for `"x64"`.

PR: https://git.openjdk.java.net/skara/pull/237