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[cmd] Improve isScheduled to be more performant when checking a single command #7096

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[cmd] Improve isScheduled to be more performant when checking a single command #7096

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795829b
Improved `isScheduled` to be more performant when checking a single c…
oh-yes-0-fps Sep 19, 2024
51ee9b9
switched to overloads to prevent unecessary array allocs on single co…
oh-yes-0-fps Sep 19, 2024
ebb91e8
ran fmt
oh-yes-0-fps Sep 20, 2024
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13 changes: 9 additions & 4 deletions wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/CommandScheduler.java
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Original file line number Diff line number Diff line change
Expand Up @@ -501,11 +501,16 @@ public void cancelAll() {
* scheduled by the scheduler; it will not work on commands inside compositions, as the scheduler
* does not see them.
*
* @param commands the command to query
* @return whether the command is currently scheduled
* @param command a single command to check
* @param commands multiple commands to check
* @return whether all of the commands are currently scheduled
*/
public boolean isScheduled(Command... commands) {
return m_scheduledCommands.containsAll(Set.of(commands));
public boolean isScheduled(Command command, Command... commands) {
if (commands.length == 0) {
return m_scheduledCommands.contains(command);
} else {
return m_scheduledCommands.contains(command) && m_scheduledCommands.containsAll(Set.of(commands));
}
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@SamCarlberg SamCarlberg Sep 19, 2024 •
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A simple loop over the array would be fine (this also avoids the Set allocation)

public boolean isScheduled(Command... commands) {
  for (var command : commands) {
    if (!m_scheduledCommands.contains(command)) {
      return false;
    }
  }

  return true;
}

Wrapping in Set.of is useful only if the same command object is passed in more than once, which should be rare or even nonexistent.

Note that a variadic argument will always create a new array, even if no objects are passed in; ie, isScheduled() effectively compiles to isScheduled(new Command[0]), so this approach doesn't prevent array allocations. If you want to avoid array object allocations, overloads for some number of predetermined parameter counts would be necessary.

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That loop would make it match the C++ version too.

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Is it worth doing the predetermined overloads? multi-command schedule checks are already uncommon

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A single-command overload would probably be fine with varargs as a fallback

}

/**
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