Remove Recursion in Session Management/Traversal (c15d6de9) · Commits · e / os / android_frameworks_base

telecomm/java/android/telecom/Logging/Session.java

+169 −71

Original line number	Diff line number	Diff line
		@@ -16,7 +16,6 @@

		package android.telecom.Logging;

		import android.annotation.NonNull;
		import android.annotation.Nullable;
		import android.os.Parcel;
		import android.os.Parcelable;
		@@ -24,8 +23,13 @@ import android.telecom.Log;
		import android.text.TextUtils;

		import com.android.internal.annotations.VisibleForTesting;
		import com.android.server.telecom.flags.Flags;

		import java.util.ArrayDeque;
		import java.util.ArrayList;
		import java.util.List;
		import java.util.Objects;
		import java.util.concurrent.atomic.AtomicInteger;

		/**
		* Stores information about a thread's point of entry into that should persist until that thread
		@@ -55,7 +59,7 @@ public class Session {
		* Initial value of mExecutionEndTimeMs and the final value of {@link #getLocalExecutionTime()}
		* if the Session is canceled.
		*/
		public static final int UNDEFINED = -1;
		public static final long UNDEFINED = -1;

		public static class Info implements Parcelable {
		public final String sessionId;
		@@ -129,46 +133,39 @@ public class Session {
		}
		}

		private String mSessionId;
		private String mShortMethodName;
		private final String mSessionId;
		private volatile String mShortMethodName;
		private long mExecutionStartTimeMs;
		private long mExecutionEndTimeMs = UNDEFINED;
		private Session mParentSession;
		private ArrayList<Session> mChildSessions;
		private volatile Session mParentSession;
		private final ArrayList<Session> mChildSessions = new ArrayList<>(5);
		private boolean mIsCompleted = false;
		private boolean mIsExternal = false;
		private int mChildCounter = 0;
		private final boolean mIsExternal;
		private final AtomicInteger mChildCounter = new AtomicInteger(0);
		// True if this is a subsession that has been started from the same thread as the parent
		// session. This can happen if Log.startSession(...) is called multiple times on the same
		// thread in the case of one Telecom entry point method calling another entry point method.
		// In this case, we can just make this subsession "invisible," but still keep track of it so
		// that the Log.endSession() calls match up.
		private boolean mIsStartedFromActiveSession = false;
		private final boolean mIsStartedFromActiveSession;
		// Optionally provided info about the method/class/component that started the session in order
		// to make Logging easier. This info will be provided in parentheses along with the session.
		private String mOwnerInfo;
		private final String mOwnerInfo;
		// Cache Full Method path so that recursive population of the full method path only needs to
		// be calculated once.
		private String mFullMethodPathCache;
		private volatile String mFullMethodPathCache;

		public Session(String sessionId, String shortMethodName, long startTimeMs,
		boolean isStartedFromActiveSession, String ownerInfo) {
		setSessionId(sessionId);
		boolean isStartedFromActiveSession, boolean isExternal, String ownerInfo) {
		mSessionId = (sessionId != null) ? sessionId : "???";
		setShortMethodName(shortMethodName);
		mExecutionStartTimeMs = startTimeMs;
		mParentSession = null;
		mChildSessions = new ArrayList<>(5);
		mIsStartedFromActiveSession = isStartedFromActiveSession;
		mIsExternal = isExternal;
		mOwnerInfo = ownerInfo;
		}

		public void setSessionId(@NonNull String sessionId) {
		if (sessionId == null) {
		mSessionId = "?";
		}
		mSessionId = sessionId;
		}

		public String getShortMethodName() {
		return mShortMethodName;
		}
		@@ -180,10 +177,6 @@ public class Session {
		mShortMethodName = shortMethodName;
		}

		public void setIsExternal(boolean isExternal) {
		mIsExternal = isExternal;
		}

		public boolean isExternal() {
		return mIsExternal;
		}
		@@ -193,13 +186,15 @@ public class Session {
		}

		public void addChild(Session childSession) {
		if (childSession != null) {
		if (childSession == null) return;
		synchronized (mChildSessions) {
		mChildSessions.add(childSession);
		}
		}

		public void removeChild(Session child) {
		if (child != null) {
		if (child == null) return;
		synchronized (mChildSessions) {
		mChildSessions.remove(child);
		}
		}
		@@ -217,7 +212,9 @@ public class Session {
		}

		public ArrayList<Session> getChildSessions() {
		return mChildSessions;
		synchronized (mChildSessions) {
		return new ArrayList<>(mChildSessions);
		}
		}

		public boolean isSessionCompleted() {
		@@ -259,17 +256,41 @@ public class Session {
		return mExecutionEndTimeMs - mExecutionStartTimeMs;
		}

		public synchronized String getNextChildId() {
		return String.valueOf(mChildCounter++);
		public String getNextChildId() {
		return String.valueOf(mChildCounter.getAndIncrement());
		}

		// Builds full session id recursively
		// Builds full session ID, which incliudes the optional external indicators (E),
		// base session ID, and the optional sub-session IDs (_X): @[E-]...[ID][_X][_Y]...
		private String getFullSessionId() {
		return getFullSessionId(0);
		if (!Flags.endSessionImprovements()) return getFullSessionIdRecursive(0);
		int currParentCount = 0;
		StringBuilder id = new StringBuilder();
		Session currSession = this;
		while (currSession != null) {
		Session parentSession = currSession.getParentSession();
		if (parentSession != null) {
		if (currParentCount >= SESSION_RECURSION_LIMIT) {
		id.insert(0, getSessionId());
		id.insert(0, TRUNCATE_STRING);
		android.util.Slog.w(LOG_TAG, "getFullSessionId: Hit iteration limit!");
		return id.toString();
		}
		if (Log.VERBOSE) {
		id.insert(0, currSession.getSessionId());
		id.insert(0, SESSION_SEPARATION_CHAR_CHILD);
		}
		} else {
		id.insert(0, currSession.getSessionId());
		}
		currSession = parentSession;
		currParentCount++;
		}
		return id.toString();
		}

		// keep track of calls and bail if we hit the recursion limit
		private String getFullSessionId(int parentCount) {
		private String getFullSessionIdRecursive(int parentCount) {
		if (parentCount >= SESSION_RECURSION_LIMIT) {
		// Don't use Telecom's Log.w here or it will cause infinite recursion because it will
		// try to add session information to this logging statement, which will cause it to hit
		@@ -286,12 +307,12 @@ public class Session {
		return mSessionId;
		} else {
		if (Log.VERBOSE) {
		return parentSession.getFullSessionId(parentCount + 1)
		return parentSession.getFullSessionIdRecursive(parentCount + 1)
		// Append "_X" to subsession to show subsession designation.
		+ SESSION_SEPARATION_CHAR_CHILD + mSessionId;
		} else {
		// Only worry about the base ID at the top of the tree.
		return parentSession.getFullSessionId(parentCount + 1);
		return parentSession.getFullSessionIdRecursive(parentCount + 1);
		}

		}
		@@ -300,16 +321,18 @@ public class Session {
		private Session getRootSession(String callingMethod) {
		int currParentCount = 0;
		Session topNode = this;
		while (topNode.getParentSession() != null) {
		Session parentNode = topNode.getParentSession();
		while (parentNode != null) {
		if (currParentCount >= SESSION_RECURSION_LIMIT) {
		// Don't use Telecom's Log.w here or it will cause infinite recursion because it
		// will try to add session information to this logging statement, which will cause
		// it to hit this condition again and so on...
		android.util.Slog.w(LOG_TAG, "getRootSession: Hit recursion limit from "
		android.util.Slog.w(LOG_TAG, "getRootSession: Hit iteration limit from "
		+ callingMethod);
		break;
		}
		topNode = topNode.getParentSession();
		topNode = parentNode;
		parentNode = topNode.getParentSession();
		currParentCount++;
		}
		return topNode;
		@@ -320,14 +343,40 @@ public class Session {
		return getRootSession("printFullSessionTree").printSessionTree();
		}

		// Recursively move down session tree using DFS, but print out each node when it is reached.
		private String printSessionTree() {
		StringBuilder sb = new StringBuilder();
		printSessionTree(0, sb, 0);
		if (!Flags.endSessionImprovements()) {
		printSessionTreeRecursive(0, sb, 0);
		return sb.toString();
		}
		int depth = 0;
		ArrayDeque<Session> deque = new ArrayDeque<>();
		deque.add(this);
		while (!deque.isEmpty()) {
		Session node = deque.pollFirst();
		sb.append("\t".repeat(depth));
		sb.append(node.toString());
		sb.append("\n");
		if (depth >= SESSION_RECURSION_LIMIT) {
		sb.append(TRUNCATE_STRING);
		depth -= 1;
		continue;
		}
		List<Session> childSessions = node.getChildSessions().reversed();
		if (!childSessions.isEmpty()) {
		depth += 1;
		for (Session child : childSessions) {
		deque.addFirst(child);
		}
		} else {
		depth -= 1;
		}
		}
		return sb.toString();
		}

		private void printSessionTree(int tabI, StringBuilder sb, int currChildCount) {
		// Recursively move down session tree using DFS, but print out each node when it is reached.
		private void printSessionTreeRecursive(int tabI, StringBuilder sb, int currChildCount) {
		// Prevent infinite recursion.
		if (currChildCount >= SESSION_RECURSION_LIMIT) {
		// Don't use Telecom's Log.w here or it will cause infinite recursion because it will
		@@ -343,26 +392,85 @@ public class Session {
		for (int i = 0; i <= tabI; i++) {
		sb.append("\t");
		}
		child.printSessionTree(tabI + 1, sb, currChildCount + 1);
		child.printSessionTreeRecursive(tabI + 1, sb, currChildCount + 1);
		}
		}

		// Recursively concatenate mShortMethodName with the parent Sessions to create full method
		// path. if truncatePath is set to true, all other external sessions (except for the most
		// recent) will be truncated to "..."
		//

		/**
		* Concatenate the short method name with the parent Sessions to create full method path.
		* @param truncatePath if truncatePath is set to true, all other external sessions (except for
		* the most recent) will be truncated to "..."
		* @return The full method path associated with this Session.
		*/
		@VisibleForTesting
		public String getFullMethodPath(boolean truncatePath) {
		StringBuilder sb = new StringBuilder();
		getFullMethodPath(sb, truncatePath, 0);
		if (!Flags.endSessionImprovements()) {
		getFullMethodPathRecursive(sb, truncatePath, 0);
		return sb.toString();
		}
		// Check to see if the session has been renamed yet. If it has not, then the session
		// has not been continued.
		Session parentSession = getParentSession();
		boolean isSessionStarted = parentSession == null
		\|\| !getShortMethodName().equals(parentSession.getShortMethodName());
		int depth = 0;
		Session currSession = this;
		while (currSession != null) {
		String cache = currSession.mFullMethodPathCache;
		// Return cached value for method path. When returning the truncated path, recalculate
		// the full path without using the cached value.
		if (!TextUtils.isEmpty(cache) && !truncatePath) {
		sb.insert(0, cache);
		return sb.toString();
		}

		private synchronized void getFullMethodPath(StringBuilder sb, boolean truncatePath,
		parentSession = currSession.getParentSession();
		// Encapsulate the external session's method name so it is obvious what part of the
		// session is external or truncate it if we do not want the entire history.
		if (currSession.isExternal()) {
		if (truncatePath) {
		sb.insert(0, TRUNCATE_STRING);
		} else {
		sb.insert(0, ")");
		sb.insert(0, currSession.getShortMethodName());
		sb.insert(0, "(");
		}
		} else {
		sb.insert(0, currSession.getShortMethodName());
		}
		if (parentSession != null) {
		sb.insert(0, SUBSESSION_SEPARATION_CHAR);
		}

		if (depth >= SESSION_RECURSION_LIMIT) {
		// Don't use Telecom's Log.w here or it will cause infinite recursion because it
		// will try to add session information to this logging statement, which will cause
		// it to hit this condition again and so on...
		android.util.Slog.w(LOG_TAG, "getFullMethodPath: Hit iteration limit!");
		sb.insert(0, TRUNCATE_STRING);
		return sb.toString();
		}
		currSession = parentSession;
		depth++;
		}
		if (isSessionStarted && !truncatePath) {
		// Cache the full method path for this node so that we do not need to calculate it
		// again in the future.
		mFullMethodPathCache = sb.toString();
		}
		return sb.toString();
		}

		private synchronized void getFullMethodPathRecursive(StringBuilder sb, boolean truncatePath,
		int parentCount) {
		if (parentCount >= SESSION_RECURSION_LIMIT) {
		// Don't use Telecom's Log.w here or it will cause infinite recursion because it will
		// try to add session information to this logging statement, which will cause it to hit
		// this condition again and so on...
		android.util.Slog.w(LOG_TAG, "getFullMethodPath: Hit recursion limit!");
		android.util.Slog.w(LOG_TAG, "getFullMethodPathRecursive: Hit recursion limit!");
		sb.append(TRUNCATE_STRING);
		return;
		}
		@@ -378,7 +486,7 @@ public class Session {
		// Check to see if the session has been renamed yet. If it has not, then the session
		// has not been continued.
		isSessionStarted = !mShortMethodName.equals(parentSession.mShortMethodName);
		parentSession.getFullMethodPath(sb, truncatePath, parentCount + 1);
		parentSession.getFullMethodPathRecursive(sb, truncatePath, parentCount + 1);
		sb.append(SUBSESSION_SEPARATION_CHAR);
		}
		// Encapsulate the external session's method name so it is obvious what part of the session
		@@ -409,14 +517,14 @@ public class Session {

		@Override
		public int hashCode() {
		int result = mSessionId != null ? mSessionId.hashCode() : 0;
		result = 31 * result + (mShortMethodName != null ? mShortMethodName.hashCode() : 0);
		result = 31 * result + (int) (mExecutionStartTimeMs ^ (mExecutionStartTimeMs >>> 32));
		result = 31 * result + (int) (mExecutionEndTimeMs ^ (mExecutionEndTimeMs >>> 32));
		int result = mSessionId.hashCode();
		result = 31 * result + mShortMethodName.hashCode();
		result = 31 * result + Long.hashCode(mExecutionStartTimeMs);
		result = 31 * result + Long.hashCode(mExecutionEndTimeMs);
		result = 31 * result + (mParentSession != null ? mParentSession.hashCode() : 0);
		result = 31 * result + (mChildSessions != null ? mChildSessions.hashCode() : 0);
		result = 31 * result + mChildSessions.hashCode();
		result = 31 * result + (mIsCompleted ? 1 : 0);
		result = 31 * result + mChildCounter;
		result = 31 * result + mChildCounter.hashCode();
		result = 31 * result + (mIsStartedFromActiveSession ? 1 : 0);
		result = 31 * result + (mOwnerInfo != null ? mOwnerInfo.hashCode() : 0);
		return result;
		@@ -432,23 +540,13 @@ public class Session {
		if (mExecutionStartTimeMs != session.mExecutionStartTimeMs) return false;
		if (mExecutionEndTimeMs != session.mExecutionEndTimeMs) return false;
		if (mIsCompleted != session.mIsCompleted) return false;
		if (mChildCounter != session.mChildCounter) return false;
		if (!(mChildCounter.get() == session.mChildCounter.get())) return false;
		if (mIsStartedFromActiveSession != session.mIsStartedFromActiveSession) return false;
		if (mSessionId != null ?
		!mSessionId.equals(session.mSessionId) : session.mSessionId != null)
		return false;
		if (mShortMethodName != null ? !mShortMethodName.equals(session.mShortMethodName)
		: session.mShortMethodName != null)
		return false;
		if (mParentSession != null ? !mParentSession.equals(session.mParentSession)
		: session.mParentSession != null)
		return false;
		if (mChildSessions != null ? !mChildSessions.equals(session.mChildSessions)
		: session.mChildSessions != null)
		return false;
		return mOwnerInfo != null ? mOwnerInfo.equals(session.mOwnerInfo)
		: session.mOwnerInfo == null;

		if (!Objects.equals(mSessionId, session.mSessionId)) return false;
		if (!Objects.equals(mShortMethodName, session.mShortMethodName)) return false;
		if (!Objects.equals(mParentSession, session.mParentSession)) return false;
		if (!Objects.equals(mChildSessions, session.mChildSessions)) return false;
		return Objects.equals(mOwnerInfo, session.mOwnerInfo);
		}

		@Override

telecomm/java/android/telecom/Logging/SessionManager.java

+93 −33

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