Option to ignore p2 mirrors via the Maven settings and the new

eclipse.p2.mirrors option

Commit 7e6d595 has removed the option for tycho.disableP2Mirrors
to use the settings.xml to disable the usage of p2 mirrors.

See https://github.com/eclipse-tycho/tycho/wiki/Frequently-asked-questions#how-do-i-disable-p2-mirrors

p2-maven-plugin/src/main/java/org/eclipse/tycho/p2maven/transport/RemoteArtifactRepositoryManagerAgentFactory.java

@@ -12,6 +12,7 @@
  *******************************************************************************/
 package org.eclipse.tycho.p2maven.transport;
 
+import org.apache.maven.plugin.LegacySupport;
 import org.codehaus.plexus.component.annotations.Component;
 import org.codehaus.plexus.component.annotations.Requirement;
 import org.codehaus.plexus.logging.Logger;
@@ -34,6 +35,9 @@ public class RemoteArtifactRepositoryManagerAgentFactory implements IAgentServic
 	@Requirement
 	MavenAuthenticator authenticator;
 
+	@Requirement
+	protected LegacySupport mavenContext;
+
 	@Override
 	public Object createService(IProvisioningAgent agent) {
 		IArtifactRepositoryManager plainRepoManager = (IArtifactRepositoryManager) new ArtifactRepositoryComponent()
@@ -45,14 +49,36 @@ public Object createService(IProvisioningAgent agent) {
 	}
 
 	private boolean getDisableP2MirrorsConfiguration() {
-		String key = "tycho.disableP2Mirrors";
-		String value = System.getProperty(key);
-		if (value != null) {
-			logger.info("Using " + key
+		String deprecatedKey = "tycho.disableP2Mirrors";
+		String deprecatedValue = getMirrorProperty(deprecatedKey);
+
+		if (deprecatedValue != null) {
+			logger.info("Using " + deprecatedKey
 					+ " to disable P2 mirrors is deprecated, use the property eclipse.p2.mirrors instead, see https://tycho.eclipseprojects.io/doc/"
 					+ TychoVersion.getTychoVersion() + "/SystemProperties.html for details.");
-			return Boolean.parseBoolean(value);
+			return Boolean.parseBoolean(deprecatedValue);
+		}
+
+		String key = "eclipse.p2.mirrors ";
+		String value = getMirrorProperty(key);
+
+		if (value != null) {
+			// eclipse.p2.mirrors false -> disable mirrors
+			return !Boolean.parseBoolean(value);
 		}
 		return false;
+
+	}
+
+	private String getMirrorProperty(String key) {
+		String value = System.getProperty(key);
+		if (key == null && mavenContext.getSession() != null) {
+			key = mavenContext.getSession().getSystemProperties().getProperty(key);
+
+			if (key == null) {
+				key = mavenContext.getSession().getUserProperties().getProperty(key);
+			}
+		}
+		return value;
 	}
 }