fix(store): remove Android and iOS plugins, closes #1256 (#1695)

The Android and iOS support introduced on #1011 is not really supported - the Tauri path API correctly resolves the cache directory on mobile, and we can access those directly using Rust code.

This is a breaking change because we no longer uses the same directory to store the files - app_cache_dir returns a different location

plugins/store/src/store.rs

@@ -2,15 +2,15 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-License-Identifier: MIT
 
-#[cfg(mobile)]
-use crate::plugin::PluginHandle;
 use crate::{ChangePayload, Error};
 use serde_json::Value as JsonValue;
 use std::{
     collections::HashMap,
+    fs::{create_dir_all, read, File},
+    io::Write,
     path::{Path, PathBuf},
 };
-use tauri::{AppHandle, Emitter, Runtime};
+use tauri::{AppHandle, Emitter, Manager, Runtime};
 
 type SerializeFn =
     fn(&HashMap<String, JsonValue>) -> Result<Vec<u8>, Box<dyn std::error::Error + Send + Sync>>;
@@ -30,20 +30,15 @@ fn default_deserialize(
 }
 
 /// Builds a [`Store`]
-pub struct StoreBuilder<R: Runtime> {
+pub struct StoreBuilder {
     path: PathBuf,
     defaults: Option<HashMap<String, JsonValue>>,
     cache: HashMap<String, JsonValue>,
     serialize: SerializeFn,
     deserialize: DeserializeFn,
-
-    #[cfg(mobile)]
-    mobile_plugin_handle: Option<PluginHandle<R>>,
-    #[cfg(not(mobile))]
-    _marker: std::marker::PhantomData<R>,
 }
 
-impl<R: Runtime> StoreBuilder<R> {
+impl StoreBuilder {
     /// Creates a new [`StoreBuilder`].
     ///
     /// # Examples
@@ -64,19 +59,9 @@ impl<R: Runtime> StoreBuilder<R> {
             cache: Default::default(),
             serialize: default_serialize,
             deserialize: default_deserialize,
-            #[cfg(mobile)]
-            mobile_plugin_handle: None,
-            #[cfg(not(mobile))]
-            _marker: std::marker::PhantomData,
         }
     }
 
-    #[cfg(mobile)]
-    pub fn mobile_plugin_handle(mut self, handle: PluginHandle<R>) -> Self {
-        self.mobile_plugin_handle = Some(handle);
-        self
-    }
-
     /// Inserts a default key-value pair.
     ///
     /// # Examples
@@ -164,7 +149,7 @@ impl<R: Runtime> StoreBuilder<R> {
     ///     Ok(())
     ///   });
     /// ```
-    pub fn build(self, app: AppHandle<R>) -> Store<R> {
+    pub fn build<R: Runtime>(self, app: AppHandle<R>) -> Store<R> {
         Store {
             app,
             path: self.path,
@@ -172,9 +157,6 @@ impl<R: Runtime> StoreBuilder<R> {
             cache: self.cache,
             serialize: self.serialize,
             deserialize: self.deserialize,
-
-            #[cfg(mobile)]
-            mobile_plugin_handle: self.mobile_plugin_handle,
         }
     }
 }
@@ -187,12 +169,43 @@ pub struct Store<R: Runtime> {
     pub(crate) cache: HashMap<String, JsonValue>,
     pub(crate) serialize: SerializeFn,
     pub(crate) deserialize: DeserializeFn,
-
-    #[cfg(mobile)]
-    pub(crate) mobile_plugin_handle: Option<PluginHandle<R>>,
 }
 
 impl<R: Runtime> Store<R> {
+    pub fn save(&self) -> Result<(), Error> {
+        let app_dir = self
+            .app
+            .path()
+            .app_data_dir()
+            .expect("failed to resolve app dir");
+        let store_path = app_dir.join(&self.path);
+
+        create_dir_all(store_path.parent().expect("invalid store path"))?;
+
+        let bytes = (self.serialize)(&self.cache).map_err(Error::Serialize)?;
+        let mut f = File::create(&store_path)?;
+        f.write_all(&bytes)?;
+
+        Ok(())
+    }
+
+    /// Update the store from the on-disk state
+    pub fn load(&mut self) -> Result<(), Error> {
+        let app_dir = self
+            .app
+            .path()
+            .app_data_dir()
+            .expect("failed to resolve app dir");
+        let store_path = app_dir.join(&self.path);
+
+        let bytes = read(store_path)?;
+
+        self.cache
+            .extend((self.deserialize)(&bytes).map_err(Error::Deserialize)?);
+
+        Ok(())
+    }
+
     pub fn insert(&mut self, key: String, value: JsonValue) -> Result<(), Error> {
         self.cache.insert(key.clone(), value.clone());
         self.app.emit(