interfaces: Extend SP with edit block like androidx.core.content.edit

Signed-off-by: Carlos Rafael Giani <crg7475@mailbox.org>

shared/src/main/java/info/nightscout/shared/sharedPreferences/SP.kt

@@ -7,6 +7,45 @@ import androidx.annotation.StringRes
  */
 
 interface SP {
+    // Using a helper Editor interface to distinguish its
+    // methods from SP's. The latter always run apply().
+    // The whole point of the edit() function below is to
+    // _avoid_ unnecessary apply() / commit() calls, so
+    // we cannot use SP's put* methods in edit().
+    interface Editor {
+        fun clear()
+
+        fun remove(@StringRes resourceID: Int)
+        fun remove(key: String)
+
+        fun putBoolean(key: String, value: Boolean)
+        fun putBoolean(@StringRes resourceID: Int, value: Boolean)
+        fun putDouble(key: String, value: Double)
+        fun putDouble(@StringRes resourceID: Int, value: Double)
+        fun putLong(key: String, value: Long)
+        fun putLong(@StringRes resourceID: Int, value: Long)
+        fun putInt(key: String, value: Int)
+        fun putInt(@StringRes resourceID: Int, value: Int)
+        fun putString(key: String, value: String)
+        fun putString(@StringRes resourceID: Int, value: String)
+    }
+
+    /**
+     * Allows for editing shared preferences in a scoped manner.
+     *
+     * This works just the same way as the androidx.core.content.edit
+     * extension does. An [Editor] instance is created and used as
+     * the receiver of [block]. When the block is done, either
+     * the shared preferences commit or apply functions are called,
+     * depending on the value of [commit].
+     *
+     * Example:
+     *
+     *     sp.edit(commit = false) {
+     *         putString("my-key", "abc123")
+     *     }
+     */
+    fun edit(commit: Boolean = false, block: Editor.() -> Unit)
 
     fun getAll(): Map<String, *>
     fun clear()

shared/src/main/java/info/nightscout/shared/sharedPreferences/SPImplementation.kt

@@ -1,7 +1,9 @@
 package info.nightscout.shared.sharedPreferences
 
+import android.annotation.SuppressLint
 import android.content.Context
 import android.content.SharedPreferences
+import androidx.annotation.StringRes
 import info.nightscout.shared.SafeParse
 import javax.inject.Inject
 import javax.inject.Singleton
@@ -12,6 +14,62 @@ class SPImplementation @Inject constructor(
     private val context: Context
 ) : SP {
 
+    @SuppressLint("ApplySharedPref")
+    override fun edit(commit: Boolean, block: SP.Editor.() -> Unit) {
+        val spEdit = sharedPreferences.edit()
+
+        val edit = object : SP.Editor {
+            override fun clear() {
+                spEdit.clear()
+            }
+
+            override fun remove(@StringRes resourceID: Int) {
+                spEdit.remove(context.getString(resourceID))
+            }
+            override fun remove(key: String) {
+                spEdit.remove(key)
+            }
+
+            override fun putBoolean(key: String, value: Boolean) {
+                spEdit.putBoolean(key, value)
+            }
+            override fun putBoolean(@StringRes resourceID: Int, value: Boolean) {
+                spEdit.putBoolean(context.getString(resourceID), value)
+            }
+            override fun putDouble(key: String, value: Double) {
+                spEdit.putString(key, value.toString())
+            }
+            override fun putDouble(@StringRes resourceID: Int, value: Double) {
+                spEdit.putString(context.getString(resourceID), value.toString())
+            }
+            override fun putLong(key: String, value: Long) {
+                spEdit.putLong(key, value)
+            }
+            override fun putLong(@StringRes resourceID: Int, value: Long) {
+                spEdit.putLong(context.getString(resourceID), value)
+            }
+            override fun putInt(key: String, value: Int) {
+                spEdit.putInt(key, value)
+            }
+            override fun putInt(@StringRes resourceID: Int, value: Int) {
+                spEdit.putInt(context.getString(resourceID), value)
+            }
+            override fun putString(key: String, value: String) {
+                spEdit.putString(key, value)
+            }
+            override fun putString(@StringRes resourceID: Int, value: String) {
+                spEdit.putString(context.getString(resourceID), value)
+            }
+        }
+
+        block(edit)
+
+        if (commit)
+            spEdit.commit()
+        else
+            spEdit.apply()
+    }
+
     override fun getAll(): Map<String, *> = sharedPreferences.all
 
     override fun clear() = sharedPreferences.edit().clear().apply()