Add extension functions to improve writability of database queries.

core-util/src/main/java/org/signal/core/util/SQLiteDatabaseExtensions.kt

@@ -1,6 +1,11 @@
 package org.signal.core.util
 
+import android.content.ContentValues
+import android.database.Cursor
+import android.database.sqlite.SQLiteDatabase
+import androidx.core.content.contentValuesOf
 import androidx.sqlite.db.SupportSQLiteDatabase
+import androidx.sqlite.db.SupportSQLiteQueryBuilder
 
 fun SupportSQLiteDatabase.getTableRowCount(table: String): Int {
   return this.query("SELECT COUNT(*) FROM $table").use {
@@ -10,4 +15,212 @@ fun SupportSQLiteDatabase.getTableRowCount(table: String): Int {
       0
     }
   }
-}
+}
+
+/**
+ * Begins a SELECT statement with a helpful builder pattern.
+ */
+fun SupportSQLiteDatabase.select(vararg columns: String): SelectBuilderPart1 {
+  return SelectBuilderPart1(this, arrayOf(*columns))
+}
+
+/**
+ * Begins an UPDATE statement with a helpful builder pattern.
+ */
+fun SupportSQLiteDatabase.update(tableName: String): UpdateBuilderPart1 {
+  return UpdateBuilderPart1(this, tableName)
+}
+
+/**
+ * Begins a DELETE statement with a helpful builder pattern.
+ */
+fun SupportSQLiteDatabase.delete(tableName: String): DeleteBuilderPart1 {
+  return DeleteBuilderPart1(this, tableName)
+}
+
+class SelectBuilderPart1(
+  private val db: SupportSQLiteDatabase,
+  private val columns: Array<String>
+) {
+  fun from(tableName: String): SelectBuilderPart2 {
+    return SelectBuilderPart2(db, columns, tableName)
+  }
+}
+
+class SelectBuilderPart2(
+  private val db: SupportSQLiteDatabase,
+  private val columns: Array<String>,
+  private val tableName: String
+) {
+  fun where(where: String, vararg whereArgs: Any): SelectBuilderPart3 {
+    return SelectBuilderPart3(db, columns, tableName, where, SqlUtil.buildArgs(whereArgs))
+  }
+
+  fun run(): Cursor {
+    return db.query(
+      SupportSQLiteQueryBuilder
+        .builder(tableName)
+        .columns(columns)
+        .create()
+    )
+  }
+}
+
+class SelectBuilderPart3(
+  private val db: SupportSQLiteDatabase,
+  private val columns: Array<String>,
+  private val tableName: String,
+  private val where: String,
+  private val whereArgs: Array<String>
+) {
+  fun orderBy(orderBy: String): SelectBuilderPart4a {
+    return SelectBuilderPart4a(db, columns, tableName, where, whereArgs, orderBy)
+  }
+
+  fun limit(limit: Int): SelectBuilderPart4b {
+    return SelectBuilderPart4b(db, columns, tableName, where, whereArgs, limit.toString())
+  }
+
+  fun run(): Cursor {
+    return db.query(
+      SupportSQLiteQueryBuilder
+        .builder(tableName)
+        .columns(columns)
+        .selection(where, whereArgs)
+        .create()
+    )
+  }
+}
+
+class SelectBuilderPart4a(
+  private val db: SupportSQLiteDatabase,
+  private val columns: Array<String>,
+  private val tableName: String,
+  private val where: String,
+  private val whereArgs: Array<String>,
+  private val orderBy: String
+) {
+  fun limit(limit: Int): SelectBuilderPart5 {
+    return SelectBuilderPart5(db, columns, tableName, where, whereArgs, orderBy, limit.toString())
+  }
+
+  fun run(): Cursor {
+    return db.query(
+      SupportSQLiteQueryBuilder
+        .builder(tableName)
+        .columns(columns)
+        .selection(where, whereArgs)
+        .orderBy(orderBy)
+        .create()
+    )
+  }
+}
+
+class SelectBuilderPart4b(
+  private val db: SupportSQLiteDatabase,
+  private val columns: Array<String>,
+  private val tableName: String,
+  private val where: String,
+  private val whereArgs: Array<String>,
+  private val limit: String
+) {
+  fun orderBy(orderBy: String): SelectBuilderPart5 {
+    return SelectBuilderPart5(db, columns, tableName, where, whereArgs, orderBy, limit)
+  }
+
+  fun run(): Cursor {
+    return db.query(
+      SupportSQLiteQueryBuilder
+        .builder(tableName)
+        .columns(columns)
+        .selection(where, whereArgs)
+        .limit(limit)
+        .create()
+    )
+  }
+}
+
+class SelectBuilderPart5(
+  private val db: SupportSQLiteDatabase,
+  private val columns: Array<String>,
+  private val tableName: String,
+  private val where: String,
+  private val whereArgs: Array<String>,
+  private val orderBy: String,
+  private val limit: String
+) {
+  fun run(): Cursor {
+    return db.query(
+      SupportSQLiteQueryBuilder
+        .builder(tableName)
+        .columns(columns)
+        .selection(where, whereArgs)
+        .orderBy(orderBy)
+        .limit(limit)
+        .create()
+    )
+  }
+}
+
+class UpdateBuilderPart1(
+  private val db: SupportSQLiteDatabase,
+  private val tableName: String
+) {
+  fun values(values: ContentValues): UpdateBuilderPart2 {
+    return UpdateBuilderPart2(db, tableName, values)
+  }
+
+  fun values(vararg values: Pair<String, Any?>): UpdateBuilderPart2 {
+    return UpdateBuilderPart2(db, tableName, contentValuesOf(*values))
+  }
+}
+
+class UpdateBuilderPart2(
+  private val db: SupportSQLiteDatabase,
+  private val tableName: String,
+  private val values: ContentValues
+) {
+  fun where(where: String, vararg whereArgs: Any): UpdateBuilderPart3 {
+    return UpdateBuilderPart3(db, tableName, values, where, SqlUtil.buildArgs(whereArgs))
+  }
+
+  fun run(conflictStrategy: Int = SQLiteDatabase.CONFLICT_NONE): Int {
+    return db.update(tableName, conflictStrategy, values, null, null)
+  }
+}
+
+class UpdateBuilderPart3(
+  private val db: SupportSQLiteDatabase,
+  private val tableName: String,
+  private val values: ContentValues,
+  private val where: String,
+  private val whereArgs: Array<String>
+) {
+  fun run(conflictStrategy: Int = SQLiteDatabase.CONFLICT_NONE): Int {
+    return db.update(tableName, conflictStrategy, values, where, whereArgs)
+  }
+}
+
+class DeleteBuilderPart1(
+  private val db: SupportSQLiteDatabase,
+  private val tableName: String
+) {
+  fun where(where: String, vararg whereArgs: Any): DeleteBuilderPart2 {
+    return DeleteBuilderPart2(db, tableName, where, SqlUtil.buildArgs(whereArgs))
+  }
+
+  fun run(): Int {
+    return db.delete(tableName, null, null)
+  }
+}
+
+class DeleteBuilderPart2(
+  private val db: SupportSQLiteDatabase,
+  private val tableName: String,
+  private val where: String,
+  private val whereArgs: Array<String>
+) {
+  fun run(): Int {
+    return db.delete(tableName, where, whereArgs)
+  }
+}