From 5f2478fb8cb1a5d82ac4e70700705004c051ac9e Mon Sep 17 00:00:00 2001
From: Jonathan Peppers <jonathan.peppers@microsoft.com>
Date: Wed, 18 Oct 2017 13:39:30 -0500
Subject: [PATCH] [build] setup a Prepare target for Xamarin.Android.sln

Context:
https://stackoverflow.com/questions/17709873/how-can-i-invoke-my-msbuild-target-when-msbuild-exe-starts-and-when-it-ends

There is a convention where an MSBuild file named
`Before.<SolutionName>.sln.targets` will get imported prior to a SLN
file getting built. This enables us to import `PrepareWindows.targets`
and enable `msbuild Xamarin.Android.sln /t:Prepare` to work
appropriately.

macOS/linux have remained unchanged, since `PrepareWindows.targets`
currently only works for Windows. `make prepare` could be ported to
MSBuild in the future.
---
 Before.Xamarin.Android.sln.targets         | 4 ++++
 README.md                                  | 4 ++--
 build-tools/scripts/PrepareWindows.targets | 4 ++--
 3 files changed, 8 insertions(+), 4 deletions(-)
 create mode 100644 Before.Xamarin.Android.sln.targets

diff --git a/Before.Xamarin.Android.sln.targets b/Before.Xamarin.Android.sln.targets
new file mode 100644
index 00000000000..a1227711520
--- /dev/null
+++ b/Before.Xamarin.Android.sln.targets
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildThisFileDirectory)build-tools\scripts\PrepareWindows.targets" Condition=" '$(OS)' == 'Windows_NT' " />
+</Project>
\ No newline at end of file
diff --git a/README.md b/README.md
index aa69df538d3..493018464d9 100644
--- a/README.md
+++ b/README.md
@@ -53,7 +53,7 @@ Building Xamarin.Android requires:
 * [Autotools (`autoconf`, `automake`, etc.)](#autotools)
 * [The Android SDK and NDK](#ndk)
 
-The `make prepare` build step (or `PrepareWindows.targets` on Windows) will
+The `make prepare` build step (or `/t:Prepare` on Windows) will
 check that all required dependencies are present.
 If you would like `make prepare` to automatically install
 required dependencies, set the `$(AutoProvision)` MSBuild property to True
@@ -246,7 +246,7 @@ Unit tests are built in a separate target:
 
 To build Xamarin.Android, ensure you are using MSBuild version 15+ and run:
 
-    msbuild build-tools\scripts\PrepareWindows.targets
+    msbuild Xamarin.Android.sln /t:Prepare
     msbuild Xamarin.Android.sln
 
 These are roughly the same as how `make prepare` and `make` are used on other platforms.
diff --git a/build-tools/scripts/PrepareWindows.targets b/build-tools/scripts/PrepareWindows.targets
index cd4bf91f7c1..521852d5704 100644
--- a/build-tools/scripts/PrepareWindows.targets
+++ b/build-tools/scripts/PrepareWindows.targets
@@ -18,12 +18,12 @@
       <Output TaskParameter="JavaSdkDirectory" PropertyName="_JavaSdkDirectory" />
     </JdkInfo>
     <Copy
-        SourceFiles="Configuration.Java.Interop.Override.props"
+        SourceFiles="$(MSBuildThisFileDirectory)Configuration.Java.Interop.Override.props"
         DestinationFiles="$(_TopDir)\external\Java.Interop\Configuration.Override.props"
         SkipUnchangedFiles="True"
     />
     <ReplaceFileContents
-        SourceFile="Windows-Configuration.OperatingSystem.props.in"
+        SourceFile="$(MSBuildThisFileDirectory)Windows-Configuration.OperatingSystem.props.in"
         DestinationFile="$(_TopDir)\Configuration.OperatingSystem.props"
         Replacements="@JAVA_HOME@=$(_JavaSdkDirectory)"
     />