[build] Add support for commercial builds (#2845)

pjcollins · jonpryor · commit 3e998b211d76 · 2019-04-10T14:59:39.000-04:00
Fixes: https://github.com/xamarin/monodroid/issues/800 Context: https://github.com/xamarin/monodroid/commit/bee5f69a0b41aaeb88fad86ce4d65960a959def9 When the Mono team works on a PR to bump mono (e.g. [PR 1536][0]), they need to deal with two different build systems: 1. The xamarin-android build system, and 2. The monodroid build system. Shocking as this may sound, the OSS xamarin-android build system gets more love from the Xamarin.Android team than the commercial monodroid build system. As such, the monodroid build system is "baroque", not well tested off of a limited number of machines, prone to peculiar breakages, and otherwise adds a level of complexity and annoyance that everyone would rather do without. Unfortunately, *because* the monodroid repo is private, we can't have the xamarin-android repo contain a "proper" git submodule to it, as that would break all external contributors. Thus, historically, the monodroid repo instead had a git submodule reference to the xamarin-android repo, which brings a *different* set of problems, e.g. the commercial builds are *always* older than the OSS builds, and accidental breakage is caught much later than we'd like. The solution? For commercial builds, instead of "starting with" the monodroid repo, which submodules xamarin-android and (not-always- correctly) builds xamarin-android, we instead have the xamarin-android repo "reference" the monodroid repo, and have "hooks" in the xamarin-android build system so that monodroid can be built *from xamarin-android*. This will simplify life for the Mono team, allow for (hopefully) easier and more frequent commercial builds, simplify integration testing of commercial builds, and hopefully result in fewer apologies from @jonpryor about monodroid builds. Now, about that "reference": if we can't use git submodules to link the monodroid repo to the xamarin-android repo, how do we maintain that reference? ~~ .external ~~ There is a (seldom-used) convention among some Xamarin projects: the [`.external`][1] file. This is a plain-text file which allows specifying external dependencies. Blank lines and lines beginning with `#` are ignored, as well as lines which don't match a valid format. The external dependency reference format is: $(RepoOwner)/$(RepoName):$(BranchName)@$(CommitHash) We will use the `.external` file in order to link a specific monodroid commit to the xamarin-android build. This file *may* be used in the future for mono, as part of the [Mono Archive][2] work. The new `make prepare-external-git-dependencies` rule will clone all git submodule references listed in the `.external` file. This rule indirectly uses the new `external-git-dependencies.targets` MSBuild file, which exposes two new targets: * `ParseExternalFile`: Parses `.external` and creates the `@(Externals)` item group, which contains item metadata: * `%(Owner)`: The GitHub owner/organization * `%(Name)`: The git repo name * `%(Branch)`: The git repo branch * `%(Identity)`: The git commit in the repo * `CheckoutExternalGitDependency`: Clones or updates the git repos specified in `@(Externals)` into `$(ExternalSourceDependencyDirectory)`, which defaults to the top-level `external` directory. The new `<ParseExternalGitDependencies/>` task which is used by the `ParseExternalFile` target, while the new `<CheckoutExternalGitDependency/>` task is used by the `CheckoutExternalGitDependency` target. `external-git-dependencies.target` is `<Import/>`ed by `xa-prep-tasks.csproj` to allow us to easily checkout, download, and process the `.external` file. ~~ Build system hooks ~~ The `make jenkins` target has been turned into a [double-colon rule][3], which allows the `make jenkins` target to be specified multiple times, in multiple files, separately. There is also now an optional [**make** `include`][4] to `external/monodroid/xa-integration.mk`. `monodroid/xa-integration.mk` overrides the `make jenkins` target so that it can integrate it's build into the xamarin-android build. ~~ Installers ~~ `OpenTK.dll` and it's related files have been removed from the installers, in an effort to start reducing the interdependencies between the monodroid & xamarin-android repos. Finally, add a way to override a portion of our installer filenames, while still using version information from xamarin-android, by setting `$(UseCommercialInstallerName)`=True. [0]: #1836 [1]: https://github.com/xamarin/external [2]: https://github.com/xamarin/xamarin-android/projects/10 [3]: https://www.gnu.org/software/make/manual/html_node/Double_002dColon.html [4]: https://www.gnu.org/software/make/manual/html_node/Include.html
diff --git a/.external b/.external
@@ -0,0 +1 @@
+xamarin/monodroid:master@97e4c3035f953076bd07f7737810810804d996db
diff --git a/.gitignore b/.gitignore
@@ -21,3 +21,4 @@ apk-sizes-*.txt
 *.binlog
 src/Xamarin.Android.Build.Tasks/Xamarin.Android.Common.props
 *~
+external/monodroid/
diff --git a/Documentation/building/unix/instructions.md b/Documentation/building/unix/instructions.md
@@ -16,7 +16,15 @@ can also be used by setting the `$(MSBUILD)` make variable to `xbuild`.
 
  4. (Optional) [Configure the build](../configuration.md).
 
- 5. Prepare the project:
+ 5. (Optional) Prepare external/proprietary git dependencies
+
+        make prepare-external-git-dependencies
+
+    This will clone or update a monodroid checkout in `external` and
+    ensure that subsequent `prepare` and `make` invocations will build
+    proprietary components.
+
+ 6. Prepare the project:
 
         make prepare
         # -or-
@@ -26,7 +34,7 @@ can also be used by setting the `$(MSBUILD)` make variable to `xbuild`.
     `git submodule update`, download NuGet dependencies, and other
     "preparatory" and pre-build tasks that need to be performed.
 
- 6. Build the project:
+ 7. Build the project:
 
         make
         # -or-
@@ -46,6 +54,17 @@ can also be used by setting the `$(MSBUILD)` make variable to `xbuild`.
         make jenkins MSBUILD=msbuild
 
 
+# Creating installers
+
+Once `make all` or `make jenkins` have completed, macOS (.pkg)
+and Windows (.vsix) installer files can be built with:
+
+    make create-installers
+
+Commercial installers will be created by this command if the
+`make prepare-external-git-dependencies` command was ran before building.
+
+
 # Building Unit Tests
 
 Once `make all` or `make jenkins` have completed, the unit tests may
diff --git a/Documentation/building/windows/instructions.md b/Documentation/building/windows/instructions.md
@@ -18,15 +18,21 @@ MSBuild version 15 or later is required.
 
  4. (Optional) [Configure the build](../configuration.md).
 
- 5. In a [Developer Command Prompt][developer-prompt], prepare the project:
+ 5. (Optional) In a [Developer Command Prompt][developer-prompt], prepare external git dependencies:
+
+        msbuild Xamarin.Android.sln /t:PrepareExternal
+
+    This will configure external proprietary components such as monodroid.
+
+ 6. In a [Developer Command Prompt][developer-prompt], prepare the project:
 
         msbuild Xamarin.Android.sln /t:Prepare
 
     This will ensure that the build dependencies are installed, perform
     `git submodule update`, download NuGet dependencies, and other
     "preparatory" and pre-build tasks that need to be performed.
 
- 6. Build the project:
+ 7. Build the project:
 
         msbuild Xamarin.Android.sln
 
diff --git a/Makefile b/Makefile
@@ -203,6 +203,17 @@ THIRD_PARTY_NOTICE_LICENSE_TYPE = microsoft-oss
 $(eval $(call CREATE_THIRD_PARTY_NOTICES_RULE,ThirdPartyNotices.txt,foundation,False,False))
 $(eval $(call CREATE_THIRD_PARTY_NOTICES_RULE,bin/$(CONFIGURATION)/lib/xamarin.android/ThirdPartyNotices.txt,$(THIRD_PARTY_NOTICE_LICENSE_TYPE),True,False))
 
+# Used by External XA Build
+EXTERNAL_XA_PATH=$(topdir)
+EXTERNAL_GIT_PATH=$(topdir)/external
+
+prepare-external-git-dependencies:
+	$(call MSBUILD_BINLOG,prep-external-tasks) build-tools/xa-prep-tasks/xa-prep-tasks.csproj
+	$(call MSBUILD_BINLOG,prep-external-checkout) build-tools/xa-prep-tasks/xa-prep-tasks.csproj \
+		/t:CheckoutExternalGitSources /p:ExternalSourceDependencyDirectory='$(EXTERNAL_GIT_PATH)'
+
+-include $(EXTERNAL_GIT_PATH)/monodroid/xa-integration.mk
+
 run-all-tests:
 	@echo "PRINTING MONO VERSION"
 	mono --version
diff --git a/build-tools/Xamarin.Android.Tools.BootstrapTasks/Xamarin.Android.Tools.BootstrapTasks.csproj b/build-tools/Xamarin.Android.Tools.BootstrapTasks/Xamarin.Android.Tools.BootstrapTasks.csproj
@@ -58,12 +58,17 @@
     <Compile Include="Xamarin.Android.Tools.BootstrapTasks\KillProcess.cs" />
     <Compile Include="Xamarin.Android.Tools.BootstrapTasks\RunUITests.cs" />
     <Compile Include="Xamarin.Android.Tools.BootstrapTasks\RunInstrumentationTests.cs" />
+    <Compile Include="Xamarin.Android.Tools.BootstrapTasks\JdkInfo.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\xa-prep-tasks\xa-prep-tasks.csproj">
       <Project>{7CE69551-BD73-4726-ACAA-AAF89C84BAF8}</Project>
       <Name>xa-prep-tasks</Name>
     </ProjectReference>
+    <ProjectReference Include="..\..\external\xamarin-android-tools\src\Xamarin.Android.Tools.AndroidSdk\Xamarin.Android.Tools.AndroidSdk.csproj">
+      <Project>{E34BCFA0-CAA4-412C-AA1C-75DB8D67D157}</Project>
+      <Name>Xamarin.Android.Tools.AndroidSdk</Name>
+    </ProjectReference>
   </ItemGroup>
   <Import Project="..\scripts\libzip-references.projitems" />
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
diff --git a/build-tools/Xamarin.Android.Tools.BootstrapTasks/Xamarin.Android.Tools.BootstrapTasks/JdkInfo.cs b/build-tools/Xamarin.Android.Tools.BootstrapTasks/Xamarin.Android.Tools.BootstrapTasks/JdkInfo.cs
@@ -7,9 +7,8 @@
 using System.IO;
 using System.Linq;
 using System.Text;
-using Xamarin.Android.Tools;
 
-namespace Xamarin.Android.BuildTools.PrepTasks
+namespace Xamarin.Android.Tools.BootstrapTasks
 {
 	public class JdkInfo : Task
 	{
@@ -40,7 +39,7 @@ public override bool Execute ()
 				} else {
 					maxVersion = new Version (MaxJdkVersion);
 				}
-				
+
 				var defaultJdk = new [] { new Tools.JdkInfo (androidSdk.JavaSdkPath) };
 				var jdk = defaultJdk.Concat (Tools.JdkInfo.GetKnownSystemJdkInfos (logger))
 					.Where (j => maxVersion != null ? j.Version <= maxVersion : true)
diff --git a/build-tools/create-pkg/create-pkg.csproj b/build-tools/create-pkg/create-pkg.csproj
@@ -9,7 +9,7 @@
     <AssemblyName>create-pkg</AssemblyName>
     <OutputPath>..\..\bin\Build$(Configuration)</OutputPath>
   </PropertyGroup>
-  <Import Project="..\..\Configuration.props" />
+  <Import Project="create-pkg.targets" />
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
     <DebugSymbols>true</DebugSymbols>
     <DebugType>full</DebugType>
@@ -29,5 +29,4 @@
     <None Include="distribution.xml.in" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
-  <Import Project="create-pkg.targets" />
 </Project>
diff --git a/build-tools/create-pkg/create-pkg.targets b/build-tools/create-pkg/create-pkg.targets
@@ -115,6 +115,7 @@
       DependsOnTargets="_FinalizePayload">
     <MakeDir Directories="$(PkgOutputPath)"/>
     <PropertyGroup>
+        <PkgProductOutputPath Condition="'$(UseCommercialInstallerName)' == 'True'">$(OutputPath)xamarin.android-$(XAVersion).pkg</PkgProductOutputPath>
         <PkgProductOutputPath Condition="'$(PkgProductOutputPath)' == ''">$(OutputPath)Xamarin.Android.Sdk-$(XAOSSInstallerSuffix).pkg</PkgProductOutputPath>
     </PropertyGroup>
     <ItemGroup>
@@ -133,5 +134,6 @@
       <ProductBuildArgs Include="&quot;$(PkgProductOutputPath)&quot;" />
     </ItemGroup>
     <Exec Command="productbuild @(ProductBuildArgs, ' ')" />
+    <RemoveDir Directories="$(OutputPath)\pkg"/>
   </Target>
 </Project>
diff --git a/build-tools/create-vsix/create-vsix.targets b/build-tools/create-vsix/create-vsix.targets
@@ -83,6 +83,7 @@
   <Target Name="_GetVsixPath"
       DependsOnTargets="GetXAVersionInfo">
     <PropertyGroup>
+      <VsixPath Condition=" '$(UseCommercialInstallerName)' == 'True' ">..\..\bin\Build$(Configuration)\$(AssemblyName)-$(XAVersion).vsix</VsixPath>
       <VsixPath Condition=" '$(VsixPath)' == '' ">..\..\bin\Build$(Configuration)\$(AssemblyName)-$(XAOSSInstallerSuffix).vsix</VsixPath>
       <_VsixDir>$([System.IO.Path]::GetDirectoryName ($(VsixPath)))</_VsixDir>
     </PropertyGroup>
diff --git a/build-tools/installers/create-installers.targets b/build-tools/installers/create-installers.targets
@@ -17,6 +17,7 @@
     <LibExtension Condition=" '$(HostOS)' == 'Linux' ">so</LibExtension>
     <LibExtension Condition=" '$(HostOS)' == 'Windows' ">dll</LibExtension>
     <IncludeMonoBundleComponents Condition="'$(IncludeMonoBuildComponents)' == ''">True</IncludeMonoBundleComponents>
+    <UseCommercialInstallerName Condition="'$(UseCommercialInstallerName)' == ''">False</UseCommercialInstallerName>
   </PropertyGroup>
   <ItemGroup>
     <_FrameworkFiles Include="$(FrameworkSrcDir)\$(FirstInstallerFrameworkVersion)\AndroidApiInfo.xml" />
@@ -189,9 +190,6 @@
   </ItemGroup>
   <!-- monodroid -->
   <ItemGroup Condition="Exists('$(MSBuildSrcDir)\Mono.Android.DebugRuntime-debug.apk')">
-    <_FrameworkFiles Include="$(FrameworkSrcDir)\$(FirstInstallerFrameworkVersion)\OpenTK.dll" />
-    <_FrameworkFiles Include="$(FrameworkSrcDir)\$(FirstInstallerFrameworkVersion)\OpenTK.pdb" />
-    <_FrameworkFilesWin Include="$(FrameworkSrcDir)\$(FirstInstallerFrameworkVersion)\OpenTK.xml" />
     <_FrameworkFilesWin Include="$(FrameworkSrcDir)\$(FirstInstallerFrameworkVersion)\Mono.Android.xml" />
     <_FrameworkFilesWin Include="$(FrameworkSrcDir)\v4.4.87\Mono.Android.xml" />
     <_FrameworkFilesWin Include="$(FrameworkSrcDir)\v5.0\Mono.Android.xml" />
diff --git a/build-tools/scripts/BuildEverything.mk b/build-tools/scripts/BuildEverything.mk
@@ -83,7 +83,7 @@ _MSBUILD_ARGS	= \
 .PHONY: leeroy jenkins leeroy-all opentk-jcw framework-assemblies
 .PHONY: create-vsix
 
-jenkins: prepare leeroy $(ZIP_OUTPUT)
+jenkins:: prepare leeroy $(ZIP_OUTPUT)
 
 leeroy: leeroy-all framework-assemblies opentk-jcw
 
diff --git a/build-tools/scripts/Packaging.mk b/build-tools/scripts/Packaging.mk
@@ -15,6 +15,7 @@ create-pkg:
 		$(if $(PACKAGE_VERSION_REV),/p:XAVersionCommitCount="$(PACKAGE_VERSION_REV)") \
 		$(if $(PKG_LICENSE_EN),/p:PkgLicenseSrcEn="$(PKG_LICENSE_EN)") \
 		$(if $(PKG_OUTPUT_PATH),/p:PkgProductOutputPath="$(PKG_OUTPUT_PATH)") \
+		$(if $(USE_COMMERCIAL_INSTALLER_NAME),/p:UseCommercialInstallerName="$(USE_COMMERCIAL_INSTALLER_NAME)") \
 		$(if $(_MSBUILD_ARGS),"$(_MSBUILD_ARGS)")
 
 create-vsix:
@@ -28,6 +29,7 @@ create-vsix:
 		$(if $(PACKAGE_HEAD_BRANCH),/p:XAVersionBranch="$(PACKAGE_HEAD_BRANCH)") \
 		$(if $(PACKAGE_VERSION_REV),/p:XAVersionCommitCount="$(PACKAGE_VERSION_REV)") \
 		$(if $(COMMIT),/p:XAVersionHash="$(COMMIT)") \
+		$(if $(USE_COMMERCIAL_INSTALLER_NAME),/p:UseCommercialInstallerName="$(USE_COMMERCIAL_INSTALLER_NAME)") \
 		$(if $(_MSBUILD_ARGS),"$(_MSBUILD_ARGS)")
 
 package-oss-name:
diff --git a/build-tools/scripts/PrepareWindows.targets b/build-tools/scripts/PrepareWindows.targets
@@ -7,8 +7,12 @@
     <_NuGetVerbosity>-Verbosity Detailed</_NuGetVerbosity>
   </PropertyGroup>
   <Import Project="$(_TopDir)\Configuration.props" />
-  <UsingTask AssemblyFile="$(_TopDir)\bin\Build$(Configuration)\xa-prep-tasks.dll" TaskName="Xamarin.Android.BuildTools.PrepTasks.JdkInfo" />
+  <UsingTask AssemblyFile="$(_TopDir)\bin\Build$(Configuration)\Xamarin.Android.Tools.BootstrapTasks.dll" TaskName="Xamarin.Android.Tools.BootstrapTasks.JdkInfo" />
   <UsingTask AssemblyFile="$(_TopDir)\bin\Build$(Configuration)\xa-prep-tasks.dll" TaskName="Xamarin.Android.BuildTools.PrepTasks.ReplaceFileContents" />
+  <Target Name="PrepareExternal">
+    <MSBuild Projects="$(MSBuildThisFileDirectory)..\xa-prep-tasks\xa-prep-tasks.csproj" />
+    <MSBuild Projects="$(MSBuildThisFileDirectory)..\xa-prep-tasks\xa-prep-tasks.csproj" Targets="CheckoutExternalGitSources"/>
+  </Target>
   <Target Name="Prepare">
     <Error
         Text="The specified `%24(AndroidToolchainDirectory)` '$(AndroidToolchainDirectory)' contains a space. Android NDK commands do not support this. Please create a Configuration.Override.props file that sets the AndroidToolchainDirectory property to a different path."
@@ -37,6 +41,7 @@
         WorkingDirectory="$(_TopDir)"
         IgnoreStandardErrorWarningFormat="True"
     />
+    <MSBuild Projects="$(MSBuildThisFileDirectory)..\Xamarin.Android.Tools.BootstrapTasks\Xamarin.Android.Tools.BootstrapTasks.csproj" />
     <MSBuild Projects="tests\Xamarin.Forms-Performance-Integration\Xamarin.Forms.Performance.Integration.csproj" Targets="Restore" />
     <MSBuild Projects="$(MSBuildThisFileDirectory)..\android-toolchain\android-toolchain.csproj" />
     <!--NOTE: need to restore test sln *after* android-toolchain has the Android SDK in place-->
diff --git a/build-tools/xa-prep-tasks/Xamarin.Android.BuildTools.PrepTasks/CheckoutExternalGitDependency.cs b/build-tools/xa-prep-tasks/Xamarin.Android.BuildTools.PrepTasks/CheckoutExternalGitDependency.cs
@@ -0,0 +1,68 @@
+﻿using System;
+using System.IO;
+using Microsoft.Build.Framework;
+
+namespace Xamarin.Android.BuildTools.PrepTasks
+{
+	public class CheckoutExternalGitDependency : Git
+	{
+		[Required]
+		public ITaskItem ExternalGitDependency { get; set; }
+
+		protected override bool LogTaskMessages {
+			get { return false; }
+		}
+
+		string commit;
+		string owner;
+		string name;
+
+		public override bool Execute ()
+		{
+			commit = ExternalGitDependency.ItemSpec;
+			owner = ExternalGitDependency.GetMetadata ("Owner");
+			name = ExternalGitDependency.GetMetadata ("Name");
+			string destination = Path.Combine (GetWorkingDirectory (), name);
+
+			if (!Directory.Exists (destination)) {
+				Clone (destination);
+			}
+
+			WorkingDirectory.ItemSpec = destination;
+			Fetch ();
+			CheckoutCommit ();
+
+			return !Log.HasLoggedErrors;
+		}
+
+		void Clone (string destination)
+		{
+			string ghToken = Environment.GetEnvironmentVariable("GH_AUTH_SECRET");
+			if (!string.IsNullOrEmpty (ghToken)) {
+				Arguments = $"clone https://{ghToken}@github.com/{owner}/{name} --progress \"{destination}\"";
+			} else {
+				// Fallback to SSH URI
+				Arguments = $"clone git@github.com:{owner}/{name} --progress \"{destination}\"";
+			}
+
+			base.Execute ();
+		}
+
+		void Fetch ()
+		{
+			Arguments = $"fetch --all --no-recurse-submodules --progress";
+			base.Execute ();
+		}
+
+		void CheckoutCommit ()
+		{
+			Arguments = $"checkout {commit} --force --progress";
+			base.Execute ();
+		}
+
+		protected override void LogToolCommand(string message)
+		{
+			// Do nothing
+		}
+	}
+}
diff --git a/build-tools/xa-prep-tasks/Xamarin.Android.BuildTools.PrepTasks/ParseExternalGitDependencies.cs b/build-tools/xa-prep-tasks/Xamarin.Android.BuildTools.PrepTasks/ParseExternalGitDependencies.cs
@@ -0,0 +1,70 @@
+﻿
+using System.Collections.Generic;
+using System.IO;
+using System.Text.RegularExpressions;
+using Microsoft.Build.Framework;
+using Microsoft.Build.Utilities;
+
+namespace Xamarin.Android.BuildTools.PrepTasks
+{
+	public class ParseExternalGitDependencies : Task
+	{
+		[Required]
+		public string ExternalFilePath { get; set; }
+		
+		/* %(ExternalGitDependencies.Owner)     - Repo owner
+		 * %(ExternalGitDependencies.Name)      - Repo name
+		 * %(ExternalGitDependencies.Branch)    - Branch name
+		 * %(ExternalGitDependencies.Identity)  - Commit hash
+		 */
+		[Output]
+		public ITaskItem[] ExternalGitDependencies { get; set; }
+
+		static readonly Regex externalRegex = new Regex (@"
+^
+\s*
+(?<comment>\#.*)
+|
+(
+  \s*
+  (?<owner>[^/]+)
+  /
+  (?<repo>[^:]+)
+  :
+  (?<branch>[^@]+)
+  @
+  (?<commit>.*)
+)
+$
+", RegexOptions.Compiled | RegexOptions.IgnorePatternWhitespace);
+
+		public override bool Execute ()
+		{
+			if (!File.Exists (ExternalFilePath)) {
+				Log.LogError($"Unable to find dependency file at: {ExternalFilePath}");
+				return false;
+			}
+
+			string[] unparsedExternals = File.ReadAllLines (ExternalFilePath);
+			var externals = new List<TaskItem> (unparsedExternals.Length);
+
+			foreach (string external in unparsedExternals) {
+				Match match = externalRegex.Match (external);
+				if (match != null && match.Success) {
+					if (match.Groups["comment"].Success) {
+						// Ignore matching lines which start with '#'.
+						continue;
+					}
+					var e = new TaskItem (match.Groups["commit"].Value);
+					e.SetMetadata ("Owner", match.Groups["owner"].Value);
+					e.SetMetadata ("Name", match.Groups["repo"].Value);
+					e.SetMetadata ("Branch", match.Groups["branch"].Value);
+					externals.Add (e);
+				}
+			}
+
+			ExternalGitDependencies = externals.ToArray ();
+			return !Log.HasLoggedErrors;
+		}
+	}
+}
diff --git a/build-tools/xa-prep-tasks/external-git-dependencies.targets b/build-tools/xa-prep-tasks/external-git-dependencies.targets
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <UsingTask AssemblyFile="..\..\bin\Build$(Configuration)\xa-prep-tasks.dll" TaskName="Xamarin.Android.BuildTools.PrepTasks.Git" />
+  <UsingTask AssemblyFile="..\..\bin\Build$(Configuration)\xa-prep-tasks.dll" TaskName="Xamarin.Android.BuildTools.PrepTasks.ParseExternalGitDependencies" />
+  <UsingTask AssemblyFile="..\..\bin\Build$(Configuration)\xa-prep-tasks.dll" TaskName="Xamarin.Android.BuildTools.PrepTasks.CheckoutExternalGitDependency" />
+  <PropertyGroup>
+    <ExternalSourceDependencyDirectory>$(XamarinAndroidSourcePath)\external</ExternalSourceDependencyDirectory>
+  </PropertyGroup>
+  <Target Name="ParseExternalFile">
+    <ParseExternalGitDependencies 
+        ExternalFilePath="$(XamarinAndroidSourcePath)\.external" >
+      <Output TaskParameter="ExternalGitDependencies" ItemName="Externals" />
+    </ParseExternalGitDependencies>
+  </Target>
+  <Target Name="CheckoutExternalGitSources"
+      DependsOnTargets="ParseExternalFile">
+    <CheckoutExternalGitDependency
+        WorkingDirectory="$(ExternalSourceDependencyDirectory)"
+        ExternalGitDependency="@(Externals)"
+    />
+  </Target>
+</Project>
diff --git a/build-tools/xa-prep-tasks/xa-prep-tasks.csproj b/build-tools/xa-prep-tasks/xa-prep-tasks.csproj

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+xamarin/monodroid:master@97e4c3035f953076bd07f7737810810804d996db`
Original file line number	Diff line number	Diff line change
`@@ -7,9 +7,8 @@`
`7`	`7`	`using System.IO;`
`8`	`8`	`using System.Linq;`
`9`	`9`	`using System.Text;`
`10`		`-using Xamarin.Android.Tools;`
`11`	`10`
`12`		`-namespace Xamarin.Android.BuildTools.PrepTasks`
	`11`	`+namespace Xamarin.Android.Tools.BootstrapTasks`
`13`	`12`	`{`
`14`	`13`	`public class JdkInfo : Task`
`15`	`14`	`{`
`@@ -40,7 +39,7 @@ public override bool Execute ()`
`40`	`39`	`} else {`
`41`	`40`	`maxVersion = new Version (MaxJdkVersion);`
`42`	`41`	`}`
`43`		`-`
	`42`	`+`
`44`	`43`	`var defaultJdk = new [] { new Tools.JdkInfo (androidSdk.JavaSdkPath) };`
`45`	`44`	`var jdk = defaultJdk.Concat (Tools.JdkInfo.GetKnownSystemJdkInfos (logger))`
`46`	`45`	`.Where (j => maxVersion != null ? j.Version <= maxVersion : true)`