Add SDK bootstrap and sdkmanager wrapper

[rmarinho]

Summary

Adds SdkManager class and sdkmanager CLI wrapper to Xamarin.Android.Tools.AndroidSdk, enabling programmatic Android SDK bootstrap and package management.

Closes #271

Architecture

Two-phase approach:

1. Bootstrap: Download command-line tools from the Google manifest feed, SHA-1 verify, extract to cmdline-tools/<version>/
2. Manage: Use the extracted sdkmanager CLI for all package operations (list, install, uninstall, update, licenses)

SdkManager is split into focused partial classes for maintainability:

File	Responsibility
SdkManager.cs	Core class, properties, constructor, IDisposable
SdkManager.Manifest.cs	Manifest download and XmlReader-based parsing
SdkManager.Bootstrap.cs	SDK bootstrap/download/extract flow
SdkManager.Packages.cs	Package list/install/uninstall/update + output parsing
SdkManager.Licenses.cs	License accept/parse/check, GetPendingLicensesAsync
SdkManager.Process.cs	Process execution via ProcessUtils, environment config

New Files

Models (Models/Sdk/):

• ChecksumType.cs — Enum for hash algorithms (SHA-256, SHA-1)
• SdkBootstrapProgress.cs — Progress reporting during bootstrap
• SdkLicense.cs — License data with Id and Text
• SdkManifestComponent.cs — Parsed manifest entry (URL, checksum, platform)
• SdkPackage.cs — Installed/available SDK package info

Utilities (extended existing files):

• DownloadUtils.cs — Added SHA-1 support, ComputeHashString shared helper, ChecksumType enum
• FileUtil.cs — Added ExtractAndInstall (safe extraction with rollback) and IsUnderDirectory

Key Features

• Manifest-driven bootstrap: XmlReader-based parsing with platform/architecture filtering
• IDisposable with ThrowIfDisposed guard on all public methods
• ANDROID_HOME only: Sets env var per Android docs; deprecated ANDROID_SDK_ROOT not used
• ANDROID_USER_HOME: Sets ~/.android so sdkmanager writes to user-writable location
• Version-based cmdline-tools directory: Installs to cmdline-tools/<version>/ (not latest/)
• Elevated execution (Windows): Detects admin-protected paths, re-launches via UAC; read-only ops skip elevation
• Zip Slip protection: Entry-by-entry extraction with path traversal validation
• Rollback on failure: Backup existing installation, restore on extract/move failure
• Cross-device fallback: Directory.Move falls back to recursive copy on IOException
• SHA-1 checksum verification of downloaded archives
• p/invoke chmod with process fallback for Unix executable permissions (throws on failure)
• ArrayPool buffers (NET5_0_OR_GREATER) for download operations
• ProcessUtils for all process execution — no direct System.Diagnostics.Process usage
• ProcessStartInfo.ArgumentList via ProcessUtils.CreateProcessStartInfo (falls back to Arguments on netstandard2.0)
• License presentation API: GetPendingLicensesAsync() returns SdkLicense objects for IDE/CLI display; AcceptLicensesAsync(IEnumerable<string>) accepts specific licenses by ID
• netstandard2.0 + net10.0 compatible, full CancellationToken support
• EnvironmentVariableNames constants used throughout (no raw strings)
• No empty catch blocks — all exceptions are logged

Coding Conventions Updated

.github/copilot-instructions.md updated with conventions established during review:

• One type per file
• Minimal public API (internal by default, InternalsVisibleTo for tests)
• Use ProcessUtils for process execution
• Use FileUtil for file operations
• File-scoped namespaces for new files
• netstandard2.0 awareness

Tests

SdkManagerTests.cs covers:

• Manifest XML parsing (components, platform filtering)
• Package list output parsing (installed, available, updates)
• License output parsing (single, multiple, none)
• Argument validation (null/empty packages → ArgumentException)
• Missing sdkmanager → InvalidOperationException (Install, Uninstall, List, Update, AcceptLicenses)
• Bootstrap null path → ArgumentNullException
• Network-dependent tests (manifest fetch, HasAcceptedLicenses) with Assert.Ignore on failure

Review Feedback Addressed

All review feedback from @jonathanpeppers and Copilot reviewer addressed:

• Removed HttpClient injection (internal only)
• Added IDisposable with dispose guard
• XmlReader instead of XElement for manifest parsing
• Version-based cmdline-tools directory (not latest/)
• ArrayPool<byte> for download buffers
• ChecksumType validated (throws NotSupportedException for unknown)
• p/invoke for chmod (throws InvalidOperationException on failure)
• EnvironmentVariableNames constants created and used
• ANDROID_SDK_ROOT removed (deprecated)
• License presentation API (GetPendingLicensesAsync + AcceptLicensesAsync with IDs)
• One type per file, no #region directives
• No empty catch blocks (all log exceptions)
• Shared ComputeHashString helper (removes duplication)
• EnumerateFiles().Any() for short-circuit
• Path.GetTempFileName() instead of manual Guid paths
• Consistent StdinPollDelayMs const for stdin polling
• Write-then-delay ordering fix in license acceptance

Co-authored-by: Copilot 223556219+Copilot@users.noreply.github.com

[Copilot]

@rmarinho I've opened a new pull request, #288, to work on those changes. Once the pull request is ready, I'll request review from you.

[jonathanpeppers]

This is really close now, but I'm also going to ask copilot to review again.

[Copilot]

Pull request overview

Copilot reviewed 17 out of 18 changed files in this pull request and generated 5 comments.

[Copilot]

Pull request overview

Copilot reviewed 17 out of 18 changed files in this pull request and generated 2 comments.