Implement PoC

.gitignore

@@ -1,2 +1,3 @@
 /target
 Cargo.lock
+/.idea

.gitmodules

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+[submodule "libfj"]
+	path = libfj
+	url = https://github.com/NGnius/libfj

Cargo.toml

@@ -1,9 +1,15 @@
 [package]
-name = "clibfj"
+name = "libfj-c"
 version = "0.1.0"
 authors = ["NGnius (Graham) <ngniusness@gmail.com>"]
 edition = "2018"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+libc = "0.2.93"
+libfj = { path = "libfj", features = ["simple"] }
+
+[lib]
+name = "libfj"
+crate-type = ["rlib", "cdylib"]

src/lib.rs

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+mod robocraft_bindings;
+
 #[cfg(test)]
 mod tests {
     #[test]

src/libfj.h

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+#ifndef LIBFJ
+#define LIBFJ
+
+typedef struct FactoryRobotListInfo_struct{
+    uint32_t item_id;
+    char* item_name;
+    char* item_description;
+    char* thumbnail; // url
+    char* added_by;
+    char* added_by_display_name;
+    char* added_date; // ISO date
+    char* expiry_date; // ISO date
+    uint32_t cpu;
+    uint32_t total_robot_ranking;
+    uint32_t rent_count;
+    uint32_t buy_count;
+    uint32_t buyable; // bool
+    char* removed_date;
+    char* ban_date;
+    uint32_t featured; // bool
+    char* banner_message;
+    float combat_rating;
+    float cosmetic_rating;
+    char* cube_amounts; // JSON as str
+} FactoryRobotListInfo;
+
+void get_factory_front_page(uint32_t size, FactoryRobotListInfo* array_ptr);
+
+#endif

src/robocraft_bindings.rs

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+use libc;
+use std::ffi::CString;
+use std::os::raw::c_char;
+use libfj::robocraft_simple as robocraft;
+use libfj::robocraft::FactoryRobotListInfo;
+
+#[repr(C)]
+pub struct FactoryRobotListInfoC {
+    pub item_id: u32,
+    pub item_name: *mut c_char,
+    pub item_description: *mut c_char,
+    pub thumbnail: *mut c_char, // url
+    pub added_by: *mut c_char,
+    pub added_by_display_name: *mut c_char,
+    pub added_date: *mut c_char, // ISO date
+    pub expiry_date: *mut c_char, // ISO date
+    pub cpu: u32,
+    pub total_robot_ranking: u32,
+    pub rent_count: u32,
+    pub buy_count: u32,
+    pub buyable: bool, // bool
+    pub removed_date: *mut c_char,
+    pub ban_date: *mut c_char,
+    pub featured: bool, // bool
+    pub banner_message: *mut c_char,
+    pub combat_rating: f32,
+    pub cosmetic_rating: f32,
+    pub cube_amounts: *mut c_char, // JSON as str
+}
+
+impl FactoryRobotListInfoC {
+    fn mock_error(msg: &str, url: &str) -> Self {
+        let mut err = Self::default();
+        err.item_name = unsafe {allocate_cstring(msg)};
+        err.thumbnail = unsafe {allocate_cstring(url)};
+        err.added_by_display_name = unsafe {allocate_cstring("ERROR")};
+        err.added_by = unsafe {allocate_cstring("ERROR")};
+        err.item_id = u32::MAX;
+        err
+    }
+}
+
+impl Default for FactoryRobotListInfoC {
+    fn default() -> Self {
+        FactoryRobotListInfoC {
+            item_id: 0,
+            item_name: unsafe {allocate_cstring("")},
+            item_description: unsafe {allocate_cstring("")},
+            thumbnail: unsafe {allocate_cstring("")},
+            added_by: unsafe {allocate_cstring("")},
+            added_by_display_name: unsafe {allocate_cstring("")},
+            added_date: unsafe {allocate_cstring("")},
+            expiry_date: unsafe {allocate_cstring("")},
+            cpu: 0,
+            total_robot_ranking: 0,
+            rent_count: 0,
+            buy_count: 0,
+            buyable: false,
+            removed_date: unsafe {allocate_cstring("")},
+            ban_date: unsafe {allocate_cstring("")},
+            featured: false,
+            banner_message: unsafe {allocate_cstring("")},
+            combat_rating: 0.0,
+            cosmetic_rating: 0.0,
+            cube_amounts: unsafe {allocate_cstring("")},
+        }
+    }
+}
+
+impl From<FactoryRobotListInfo> for FactoryRobotListInfoC {
+    fn from(frli: FactoryRobotListInfo) -> Self {
+        let def = "".to_string();
+        FactoryRobotListInfoC {
+            item_id: frli.item_id as u32,
+            item_name: unsafe {allocate_cstring(&frli.item_name)},
+            item_description: unsafe {allocate_cstring(&frli.item_description)},
+            thumbnail: unsafe {allocate_cstring(&frli.thumbnail)},
+            added_by: unsafe {allocate_cstring(&frli.added_by)},
+            added_by_display_name: unsafe {allocate_cstring(&frli.added_by_display_name)},
+            added_date: unsafe {allocate_cstring(&frli.added_date)},
+            expiry_date: unsafe {allocate_cstring(&frli.expiry_date)},
+            cpu: frli.cpu  as u32,
+            total_robot_ranking: frli.total_robot_ranking  as u32,
+            rent_count: frli.rent_count  as u32,
+            buy_count: frli.buy_count as u32,
+            buyable: frli.buyable,
+            removed_date: unsafe {allocate_cstring(&frli.removed_date.unwrap_or(def.clone()))},
+            ban_date: unsafe {allocate_cstring(&frli.ban_date.unwrap_or(def.clone()))},
+            featured: frli.featured,
+            banner_message: unsafe {allocate_cstring(&frli.banner_message.unwrap_or(def.clone()))},
+            combat_rating: frli.combat_rating,
+            cosmetic_rating: frli.cosmetic_rating,
+            cube_amounts: unsafe {allocate_cstring(&frli.cube_amounts)},
+        }
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn get_factory_front_page(items: libc::c_uint, array_ptr: *mut FactoryRobotListInfoC) {
+    if items == 0 {return;} // nothing to populate, so it's useless to do work
+    let factory_api = robocraft::FactoryAPI::new();
+    let result = factory_api.list();
+    if let Ok(info) = result {
+        let max = if info.response.roboshop_items.len() < (items as usize) { info.response.roboshop_items.len() } else {items as usize};
+        let c_result = std::slice::from_raw_parts_mut(array_ptr, items as usize);
+        // copy results to output array
+        for i in 0..max {
+            c_result[i] = info.response.roboshop_items[i].clone().into();
+        }
+    } else if let Err(e) = result {
+        println!("{}", e);
+        // place error info into first array item
+        let c_result = std::slice::from_raw_parts_mut(array_ptr, items as usize);
+        c_result[0] = FactoryRobotListInfoC::mock_error(
+            &format!("{}", &e),
+            ""
+        );
+    }
+}
+
+unsafe fn allocate_cstring(input: &str) -> *mut c_char {
+    let input_c = CString::new(input).expect("Rust &str -> CString conversion failed");
+    let space = libc::malloc(libc::strlen(input_c.as_ptr()) + 1) as *mut c_char;
+    libc::strcpy(space, input_c.as_ptr());
+    return space;
+}