From 0c12d43b61c36f9dc54842581d2d2bbead7b5a20 Mon Sep 17 00:00:00 2001
From: Yifan Wu <shinbokuow@163.com>
Date: Tue, 8 Dec 2020 10:43:24 +0800
Subject: [PATCH] Get app data by name.

---
 os/build.rs      |  7 +++++++
 os/src/loader.rs | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/os/build.rs b/os/build.rs
index 792fe3c4..389587aa 100644
--- a/os/build.rs
+++ b/os/build.rs
@@ -34,6 +34,13 @@ _num_app:
     }
     writeln!(f, r#"    .quad app_{}_end"#, apps.len() - 1)?;
 
+    writeln!(f, r#"
+    .global _app_names
+_app_names:"#)?;
+    for app in apps.iter() {
+        writeln!(f, r#"    .string "{}\n""#, app)?;
+    }
+
     for (idx, app) in apps.iter().enumerate() {
         println!("app_{}: {}", idx, app);
         writeln!(f, r#"
diff --git a/os/src/loader.rs b/os/src/loader.rs
index 6d284743..1a23b979 100644
--- a/os/src/loader.rs
+++ b/os/src/loader.rs
@@ -1,3 +1,5 @@
+use alloc::vec::Vec;
+
 pub fn get_num_app() -> usize {
     extern "C" { fn _num_app(); }
     unsafe { (_num_app as usize as *const usize).read_volatile() }
@@ -18,3 +20,33 @@ pub fn get_app_data(app_id: usize) -> &'static [u8] {
         )
     }
 }
+
+#[allow(unused)]
+pub fn get_app_data_by_name(name: &str) -> Option<&'static [u8]> {
+    let num_app = get_num_app();
+    let app_names = app_names();
+    (0..num_app)
+        .find(|&i| app_names[i] == name)
+        .map(|i| get_app_data(i))
+}
+
+#[allow(unused)]
+fn app_names() -> Vec<&'static str> {
+    let num_app = get_num_app();
+    extern "C" { fn _app_names(); }
+    let mut start = _app_names as usize as *const u8;
+    let mut v = Vec::new();
+    unsafe {
+        for _ in 0..num_app {
+            let mut end = start;
+            while end.read_volatile() != '\n' as u8 {
+                end = end.add(1);
+            }
+            let slice = core::slice::from_raw_parts(start, end as usize - start as usize);
+            let str = core::str::from_utf8(slice).unwrap();
+            v.push(str);
+            start = end.add(1);
+        }
+    }
+    v
+}