refactor: Prefer System.currentTimeMillis() to Date().getTime() (#645)

Avoids unnecessary object creation.

Add a lint rule to catch this.

app/src/main/java/app/pachli/adapter/ReportNotificationViewHolder.kt

@@ -34,7 +34,6 @@ import app.pachli.util.StatusDisplayOptions
 import app.pachli.util.getRelativeTimeSpanString
 import app.pachli.viewdata.NotificationViewData
 import at.connyduck.sparkbutton.helpers.Utils
-import java.util.Date
 
 class ReportNotificationViewHolder(
     private val binding: ItemReportNotificationBinding,
@@ -90,7 +89,7 @@ class ReportNotificationViewHolder(
         )
         binding.notificationSummary.text = itemView.context.getString(
             R.string.notification_summary_report_format,
-            getRelativeTimeSpanString(itemView.context, report.createdAt.time, Date().time),
+            getRelativeTimeSpanString(itemView.context, report.createdAt.time, System.currentTimeMillis()),
             report.statusIds?.size ?: 0,
         )
         binding.notificationCategory.text = getTranslatedCategory(itemView.context, report.category)

app/src/main/java/app/pachli/components/compose/MediaUploader.kt

@@ -42,7 +42,6 @@ import java.io.File
 import java.io.FileInputStream
 import java.io.FileOutputStream
 import java.io.IOException
-import java.util.Date
 import javax.inject.Inject
 import javax.inject.Singleton
 import kotlinx.coroutines.CoroutineScope
@@ -271,7 +270,7 @@ class MediaUploader @Inject constructor(
             val fileExtension = map.getExtensionFromMimeType(mimeType)
             val filename = "%s_%s_%s.%s".format(
                 context.getString(R.string.app_name),
-                Date().time.toString(),
+                System.currentTimeMillis().toString(),
                 randomAlphanumericString(10),
                 fileExtension,
             )

app/src/main/java/app/pachli/components/notifications/SeveredRelationshipsViewHolder.kt

@@ -26,7 +26,6 @@ import app.pachli.databinding.ItemSeveredRelationshipsBinding
 import app.pachli.util.StatusDisplayOptions
 import app.pachli.util.getRelativeTimeSpanString
 import app.pachli.viewdata.NotificationViewData
-import java.util.Date
 
 class SeveredRelationshipsViewHolder(
     private val binding: ItemSeveredRelationshipsBinding,
@@ -42,7 +41,7 @@ class SeveredRelationshipsViewHolder(
                 HtmlCompat.FROM_HTML_MODE_LEGACY,
             )
 
-            binding.datetime.text = getRelativeTimeSpanString(itemView.context, event.createdAt.time, Date().time)
+            binding.datetime.text = getRelativeTimeSpanString(itemView.context, event.createdAt.time, System.currentTimeMillis())
 
             binding.notificationSummary.text = itemView.context.resources.getQuantityString(
                 R.plurals.notification_severed_relationships_summary_report_fmt,
@@ -59,7 +58,7 @@ class SeveredRelationshipsViewHolder(
             binding.notificationCategory.text = itemView.context.getString(resourceId)
         } else {
             if (payloads.any { it == StatusBaseViewHolder.Key.KEY_CREATED }) {
-                binding.datetime.text = getRelativeTimeSpanString(itemView.context, event.createdAt.time, Date().time)
+                binding.datetime.text = getRelativeTimeSpanString(itemView.context, event.createdAt.time, System.currentTimeMillis())
             }
         }
     }

app/src/main/java/app/pachli/components/notifications/StatusNotificationViewHolder.kt

@@ -173,7 +173,7 @@ internal class StatusNotificationViewHolder(
             val readoutAloud: CharSequence
             if (createdAt != null) {
                 val then = createdAt.time
-                val now = Date().time
+                val now = System.currentTimeMillis()
                 readout = getRelativeTimeSpanString(binding.statusMetaInfo.context, then, now)
                 readoutAloud = DateUtils.getRelativeTimeSpanString(
                     then,

checks/src/main/java/app/pachli/lint/checks/DateDotTimeDetector.kt

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2024 Pachli Association
+ *
+ * This file is a part of Pachli.
+ *
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * Pachli is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
+ * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with Pachli; if not,
+ * see <http://www.gnu.org/licenses>.
+ */
+
+package app.pachli.lint.checks
+
+import com.android.tools.lint.checks.DataFlowAnalyzer
+import com.android.tools.lint.detector.api.Category
+import com.android.tools.lint.detector.api.Detector
+import com.android.tools.lint.detector.api.Implementation
+import com.android.tools.lint.detector.api.Issue
+import com.android.tools.lint.detector.api.JavaContext
+import com.android.tools.lint.detector.api.LintFix
+import com.android.tools.lint.detector.api.Scope
+import com.android.tools.lint.detector.api.Severity
+import com.android.tools.lint.detector.api.SourceCodeScanner
+import com.intellij.psi.PsiMethod
+import org.jetbrains.uast.UCallExpression
+import org.jetbrains.uast.UMethod
+import org.jetbrains.uast.getParentOfType
+
+class DateDotTimeDetector : Detector(), SourceCodeScanner {
+    override fun getApplicableConstructorTypes(): List<String> = listOf(CLASS_DATE)
+
+    val fix = LintFix.create()
+        .name("Replace with `System.currentTimeMillis()`")
+        .replace()
+        .text("Date().time")
+        .with("System.currentTimeMillis()")
+        .independent(true)
+        .build()
+
+    // Look for a Date() constructor call followed by a getTime() method call
+    override fun visitConstructor(context: JavaContext, node: UCallExpression, constructor: PsiMethod) {
+        val method = node.getParentOfType(UMethod::class.java) ?: return
+        val analyzer = object : DataFlowAnalyzer(listOf(node)) {
+            var reported = false
+
+            override fun receiver(call: UCallExpression) {
+                if (reported) return
+                if (call.methodName != METHOD_GET_TIME) return
+
+                reported = true
+                context.report(
+                    issue = ISSUE,
+                    scope = node,
+                    location = context.getCallLocation(call, includeReceiver = true, includeArguments = true),
+                    message = "Use `System.currentTimeMillis()`",
+                    quickfixData = fix,
+                )
+            }
+        }
+        method.accept(analyzer)
+    }
+
+    companion object {
+        private const val CLASS_DATE = "java.util.Date"
+        private const val METHOD_GET_TIME = "getTime"
+
+        val ISSUE = Issue.create(
+            id = "DateDotTimeDetector",
+            briefDescription = "Don't use `Date().time`, use `System.currentTimeMillis()`",
+            explanation = """
+                Calling `Date().time` / `Date().getTime()` is unnecessary object creation. Use
+                `System.currentTimeMillis()` to avoid this.
+            """,
+            category = Category.CORRECTNESS,
+            priority = 6,
+            severity = Severity.WARNING,
+            implementation = Implementation(
+                DateDotTimeDetector::class.java,
+                Scope.JAVA_FILE_SCOPE,
+            ),
+        )
+    }
+}

checks/src/main/java/app/pachli/lint/checks/LintRegistry.kt

@@ -10,6 +10,7 @@ class LintRegistry : IssueRegistry() {
     override val issues: List<Issue>
         get() = listOf(
             AndroidxToolbarDetector.ISSUE,
+            DateDotTimeDetector.ISSUE,
             IntentDetector.ISSUE,
         )
 

checks/src/test/java/app/pachli/lint/checks/DateDotTimeDetectorTest.kt

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2024 Pachli Association
+ *
+ * This file is a part of Pachli.
+ *
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * Pachli is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
+ * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with Pachli; if not,
+ * see <http://www.gnu.org/licenses>.
+ */
+
+package app.pachli.lint.checks
+
+import com.android.tools.lint.checks.infrastructure.LintDetectorTest
+import com.android.tools.lint.checks.infrastructure.TestMode
+import com.android.tools.lint.detector.api.Detector
+import com.android.tools.lint.detector.api.Issue
+
+@Suppress("ktlint:standard:function-naming")
+class DateDotTimeDetectorTest : LintDetectorTest() {
+    override fun getDetector(): Detector = DateDotTimeDetector()
+
+    override fun getIssues(): List<Issue> = listOf(DateDotTimeDetector.ISSUE)
+
+    fun `test Intent component constructor emits warning`() {
+        lint().files(
+            kotlin(
+                """
+                package test.pkg
+
+                import java.util.Date
+
+                fun getTimeMills() = Date().time
+            """,
+
+            ).indented(),
+        ).allowMissingSdk().testModes(TestMode.DEFAULT).run().expect(
+            """src/test/pkg/test.kt:5: Warning: Use System.currentTimeMillis() [DateDotTimeDetector]
+fun getTimeMills() = Date().time
+                     ~~~~~~~~~~~
+0 errors, 1 warnings""",
+        )
+    }
+}