feat(core): reimplement readTextFile for performance (#3631)

.changes/read-fs-read-file.md

@@ -0,0 +1,6 @@
+---
+"tauri": patch
+"api": patch
+---
+
+Reimplement endpoint to read file as string for performance.

core/tauri/src/endpoints/file_system.rs

@@ -72,11 +72,16 @@ pub struct FileOperationOptions {
 #[derive(Deserialize, CommandModule)]
 #[serde(tag = "cmd", rename_all = "camelCase")]
 pub enum Cmd {
-  /// The read text file API.
+  /// The read binary file API.
   ReadFile {
     path: SafePathBuf,
     options: Option<FileOperationOptions>,
   },
+  /// The read binary file API.
+  ReadTextFile {
+    path: SafePathBuf,
+    options: Option<FileOperationOptions>,
+  },
   /// The write file API.
   WriteFile {
     path: SafePathBuf,
@@ -137,6 +142,24 @@ impl Cmd {
       .map_err(Into::into)
   }
 
+  #[module_command_handler(fs_read_file, "fs > readFile")]
+  fn read_text_file<R: Runtime>(
+    context: InvokeContext<R>,
+    path: SafePathBuf,
+    options: Option<FileOperationOptions>,
+  ) -> super::Result<String> {
+    let resolved_path = resolve_path(
+      &context.config,
+      &context.package_info,
+      &context.window,
+      path,
+      options.and_then(|o| o.dir),
+    )?;
+    file::read_string(&resolved_path)
+      .with_context(|| format!("path: {}", resolved_path.0.display()))
+      .map_err(Into::into)
+  }
+
   #[module_command_handler(fs_write_file, "fs > writeFile")]
   fn write_file<R: Runtime>(
     context: InvokeContext<R>,

tooling/api/src/fs.ts

@@ -139,14 +139,14 @@ async function readTextFile(
   filePath: string,
   options: FsOptions = {}
 ): Promise<string> {
-  return invokeTauriCommand<number[]>({
+  return invokeTauriCommand<string>({
     __tauriModule: 'Fs',
     message: {
-      cmd: 'readFile',
+      cmd: 'readTextFile',
       path: filePath,
       options
     }
-  }).then((data) => new TextDecoder().decode(new Uint8Array(data)))
+  })
 }
 
 /**