OncePerPeriodInterceptor.kt

TLDR

The OncePerPeriodInterceptor class is a heap analysis interceptor that allows a chain of heap analysis jobs to proceed only once per specified period of time.

Methods

intercept

This method intercepts the heap analysis job chain and checks if enough time has elapsed since the last analysis. If not enough time has passed, it cancels the job. If enough time has passed, it proceeds with the job and updates the last start timestamp in the shared preferences.

forget

This method clears the shared preferences, effectively forgetting the last start timestamp.

Classes

None

package leakcanary

import android.app.Application
import android.content.Context
import android.content.SharedPreferences
import leakcanary.HeapAnalysisInterceptor.Chain
import leakcanary.HeapAnalysisJob.Result
import java.util.concurrent.TimeUnit

/**
 * Proceeds once per [period] (of time) and then cancels all follow up jobs until [period] has
 * passed.
 */
class OncePerPeriodInterceptor(
  application: Application,
  private val periodMillis: Long = TimeUnit.DAYS.toMillis(1)
) : HeapAnalysisInterceptor {

  private val preference: SharedPreferences by lazy {
    application.getSharedPreferences("OncePerPeriodInterceptor", Context.MODE_PRIVATE)!!
  }

  override fun intercept(chain: Chain): Result {
    val lastStartTimestamp = preference.getLong(LAST_START_TIMESTAMP_KEY, 0)
    val now = System.currentTimeMillis()
    val elapsedMillis = now - lastStartTimestamp

    if (elapsedMillis < periodMillis) {
      chain.job.cancel("not enough time elapsed since last analysis: elapsed $elapsedMillis ms < period $periodMillis ms")
    }

    return chain.proceed().apply {
      if (this is Result.Done) {
        preference.edit().putLong(LAST_START_TIMESTAMP_KEY, now).apply()
      }
    }
  }

  fun forget() {
    preference.edit().clear().apply()
  }

  companion object {
    private const val LAST_START_TIMESTAMP_KEY = "last_start_timestamp"
  }
}