From a4feab38468b728c97d9102de32ece0c84bdf529 Mon Sep 17 00:00:00 2001
From: Dnomd343 <i@343.re>
Date: Mon, 6 Mar 2023 03:33:57 +0800
Subject: [PATCH] fix: rust c-style string

---
 include/utils/assets.h |  3 +-
 src/assets/src/ffi.rs  | 66 ++++++++++++++++++++++++++++++++++++++++++
 src/assets/src/lib.rs  | 34 ++--------------------
 src/cleardns.c         | 29 +++++++++++++------
 4 files changed, 91 insertions(+), 41 deletions(-)
 create mode 100644 src/assets/src/ffi.rs

diff --git a/include/utils/assets.h b/include/utils/assets.h
index cf75abf..2000b48 100644
--- a/include/utils/assets.h
+++ b/include/utils/assets.h
@@ -14,7 +14,8 @@ void assets_extract();
 
 // RUST DEMO START
 
-void rust_test(const char *const *ptr);
+void rust_test_single(const char *ptr);
+void rust_test_multi(const char *const *ptr);
 
 // RUST DEMO END
 
diff --git a/src/assets/src/ffi.rs b/src/assets/src/ffi.rs
new file mode 100644
index 0000000..746533b
--- /dev/null
+++ b/src/assets/src/ffi.rs
@@ -0,0 +1,66 @@
+use std::ffi::{CStr, CString};
+use std::os::raw::c_char;
+
+/// Load c-style string from `char *` pointer.
+unsafe fn load_c_string(ptr: *const c_char) -> String {
+
+    println!("c-style ptr:     {:?}", ptr);
+
+    // let s = CStr::from_ptr(ptr).to_str().unwrap();
+    //
+    // println!("rust cstr ptr:   {:?}", s.as_ptr());
+    //
+    // let string = format!("{}", s);
+    //
+    // println!("rust string ptr: {:?}", string.as_ptr());
+    //
+    // println!();
+
+
+    let a = CString::from(CStr::from_ptr(ptr));
+    println!("rust string ptr: {:?}", a.as_ptr());
+
+    a.into_string().unwrap()
+
+    // String::from(CStr::from_ptr(ptr).to_str().unwrap())
+}
+
+/// Load c-style string list from `char **` pointer.
+unsafe fn load_c_string_list(ptr: *const *const c_char) -> Vec<String> {
+    let mut index = 0;
+    let mut string_list: Vec<String> = vec![];
+    while *ptr.offset(index) != std::ptr::null() { // traverse until `NULL`
+        let s = load_c_string(*ptr.offset(index));
+
+        // println!("string ptr: `{:?}`", s.as_ptr());
+        println!("content: `{}`", s);
+
+        println!();
+
+        string_list.push(s);
+
+        index += 1;
+    }
+    string_list
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn rust_test_single(ptr: *const c_char) {
+    println!("enter rust function");
+
+    let ret = load_c_string(ptr);
+    println!("ret: {:?}", ret);
+
+    println!("exit rust function");
+}
+
+
+#[no_mangle]
+pub unsafe extern "C" fn rust_test_multi(ptr: *const *const c_char) {
+    println!("enter rust function");
+
+    let ret = load_c_string_list(ptr);
+    println!("ret: {:?}", ret);
+
+    println!("exit rust function");
+}
diff --git a/src/assets/src/lib.rs b/src/assets/src/lib.rs
index ac11b25..9097f4b 100644
--- a/src/assets/src/lib.rs
+++ b/src/assets/src/lib.rs
@@ -4,42 +4,14 @@
 //
 // use crate::fetch::Asset;
 
-use std::ffi::{c_char, CStr};
+mod ffi;
+
+// use std::ffi::{c_char, CStr};
 
 // const TIMEOUT: u64 = 60;
 //
 // const ASSETS_DIR: &str = "/cleardns/assets/";
 
-#[no_mangle]
-pub unsafe extern "C" fn rust_test(ptr: *const *const c_char) {
-    println!("enter rust function");
-
-    unsafe {
-
-        println!("ptr: {:?}", ptr);
-
-
-        let mut index = 0;
-        while *ptr.offset(index) != std::ptr::null() {
-
-            let p = *ptr.offset(index);
-
-            println!("loop: {:?}", p);
-
-            let s = String::from(
-                CStr::from_ptr(p).to_str().unwrap()
-            );
-
-            println!("content: {}", s);
-
-            index += 1;
-        }
-
-
-    }
-
-    println!("exit rust function");
-}
 
 // #[tokio::main]
 // async fn main() {
diff --git a/src/cleardns.c b/src/cleardns.c
index 1225691..a2d940d 100644
--- a/src/cleardns.c
+++ b/src/cleardns.c
@@ -120,22 +120,33 @@ void cleardns() { // cleardns service
 int main(int argc, char *argv[]) {
 
     char **demo = string_list_init();
-    string_list_append(&demo, "item 1");
-    string_list_append(&demo, "item 2");
-    string_list_append(&demo, "item 3");
+    string_list_append(&demo, "item 1 afdcafaed");
+    string_list_append(&demo, "item 2 fasdfcade");
+    string_list_append(&demo, "item 3 fadfa");
+    string_list_append(&demo, "item 4");
+    string_list_append(&demo, "item 5");
 
     char *tmp = string_list_dump(demo);
     log_warn("dump -> %s", tmp);
 
     string_list_free(demo);
 
-    log_info("string list -> %p", demo);
-    log_info("string list 1 -> %p", demo[0]);
-    log_info("string list 2 -> %p", demo[1]);
-    log_info("string list 3 -> %p", demo[2]);
-    log_info("string list 4 -> %p", demo[3]);
+    log_info("string list -> %p -> %p", &demo, demo);
+    log_info("string list 1 -> %p -> %p -> `%s`", &demo[0], demo[0], demo[0]);
+    log_info("string list 2 -> %p -> %p -> `%s`", &demo[1], demo[1], demo[1]);
+    log_info("string list 3 -> %p -> %p -> `%s`", &demo[2], demo[2], demo[2]);
+    log_info("string list 4 -> %p -> %p -> `%s`", &demo[3], demo[3], demo[3]);
+    log_info("string list 5 -> %p -> %p -> `%s`", &demo[4], demo[4], demo[4]);
+    log_info("string list 6 -> %p -> %p -> `%s`", &demo[5], demo[5], demo[5]);
+
+//    rust_test_single(demo[0]);
+//    rust_test_single(demo[1]);
+//    rust_test_single(demo[2]);
+//    rust_test_single(demo[3]);
+//    rust_test_single(demo[4]);
+//
+    rust_test_multi(demo);
 
-    rust_test(demo);
 
     log_warn("test end");
     exit(0);