c: rename nostr-sdk-cpp to nostr-sdk-c

* Support both for C and C++
* Use `cbindgen` instead of `cxx`

Signed-off-by: Yuki Kishimoto <[email protected]>

Cargo.toml

@@ -1,6 +1,6 @@
 [workspace]
 members = [
-    "bindings/nostr-sdk-cpp",
+    "bindings/nostr-sdk-c",
     "bindings/nostr-sdk-ffi",
     "bindings/nostr-sdk-js",
     "bindings/uniffi-bindgen",

bindings/README.md

@@ -4,8 +4,8 @@
     * [nostr-sdk-ffi](./nostr-sdk-ffi): UniFFI bindings of the [nostr] and [nostr-sdk] crates
 - JavaScript:
     * [nostr-sdk-js](./nostr-sdk-js): JavaScript bindings of the [nostr] and [nostr-sdk] crates
-- C++:
-    * [nostr-sdk-cpp](./nostr-sdk-cpp): C++ bindings of the [nostr] and [nostr-sdk] crates
+- C/C++:
+    * [nostr-sdk-c](./nostr-sdk-c): C/C++ bindings of the [nostr] and [nostr-sdk] crates
 
 [nostr]: ../crates/nostr/
 [nostr-sdk]: ../crates/nostr-sdk/

bindings/nostr-sdk-c/.gitignore

@@ -0,0 +1,3 @@
+bin/
+build/
+include/*.h

bindings/nostr-sdk-cpp/Cargo.toml → bindings/nostr-sdk-c/Cargo.toml

@@ -1,5 +1,5 @@
 [package]
-name = "nostr-sdk-cpp"
+name = "nostr-sdk-c"
 version = "0.1.0"
 edition = "2021"
 publish = false
@@ -8,13 +8,10 @@ publish = false
 crate-type = ["staticlib"]
 
 [dependencies]
-anyhow = "1.0"
-cxx = "1.0"
 nostr-sdk = { workspace = true, features = ["all-nips"] }
 tokio = { workspace = true, features = ["full"] }
 tracing = { workspace = true, features = ["std"] }
 tracing-subscriber.workspace = true
 
 [build-dependencies]
-cxx-build = "1.0"
-glob = "0.3"
+cbindgen = "0.27"

bindings/nostr-sdk-cpp/README.md → bindings/nostr-sdk-c/README.md

@@ -1,4 +1,4 @@
-# Nostr SDK for C++
+# C/C++ bindings for Nostr SDK
 
 ## Supported NIPs
 

bindings/nostr-sdk-c/build.rs

@@ -0,0 +1,37 @@
+// Copyright (c) 2022-2023 Yuki Kishimoto
+// Copyright (c) 2023-2024 Rust Nostr Developers
+// Distributed under the MIT software license
+
+use std::env;
+use std::process::Command;
+
+use cbindgen::{Config, Error, Language};
+
+fn main() {
+    if let Ok(output) = Command::new("git").args(["rev-parse", "HEAD"]).output() {
+        if let Ok(git_hash) = String::from_utf8(output.stdout) {
+            println!("cargo:rerun-if-changed={git_hash}");
+            println!("cargo:rustc-env=GIT_HASH={git_hash}");
+        }
+    }
+
+    let crate_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
+    let config: Config = config();
+    cbindgen::generate_with_config(&crate_dir, config).map_or_else(
+        |error| match error {
+            Error::ParseSyntaxError { .. } => {}
+            e => panic!("{:?}", e),
+        },
+        |bindings| {
+            bindings.write_to_file("include/nostr_sdk.h");
+        },
+    );
+}
+
+fn config() -> Config {
+    let mut config: Config = Config::default();
+    config.language = Language::C;
+    config.cpp_compat = true;
+    config.documentation = true;
+    config
+}

bindings/nostr-sdk-c/examples/client.c

@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <string.h>
+
+#include <nostr_sdk.h>
+
+int main() {
+    // Init logger
+    enum LogLevel level = Debug;
+    init_logger(level);
+
+    // New client without signer
+    const Client* client = client_without_signer();
+
+    // Add relays
+    client_add_relay(client, "wss://relay.damus.io");
+
+    // Connect
+    client_connect(client);
+
+    // Send event
+    const char* json = "{\"content\":\"Think about this.\\n\\nThe most powerful centralized institutions in the world have been replaced by a protocol that protects the individual. #bitcoin\\n\\nDo you doubt that we can replace everything else?\\n\\nBullish on the future of humanity\\nnostr:nevent1qqs9ljegkuk2m2ewfjlhxy054n6ld5dfngwzuep0ddhs64gc49q0nmqpzdmhxue69uhhyetvv9ukzcnvv5hx7un8qgsw3mfhnrr0l6ll5zzsrtpeufckv2lazc8k3ru5c3wkjtv8vlwngksrqsqqqqqpttgr27\",\"created_at\":1703184271,\"id\":\"38acf9b08d06859e49237688a9fd6558c448766f47457236c2331f93538992c6\",\"kind\":1,\"pubkey\":\"e8ed3798c6ffebffa08501ac39e271662bfd160f688f94c45d692d8767dd345a\",\"sig\":\"f76d5ecc8e7de688ac12b9d19edaacdcffb8f0c8fa2a44c00767363af3f04dbc069542ddc5d2f63c94cb5e6ce701589d538cf2db3b1f1211a96596fabb6ecafe\",\"tags\":[[\"e\",\"5fcb28b72cadab2e4cbf7311f4acf5f6d1a99a1c2e642f6b6f0d5518a940f9ec\",\"\",\"mention\"],[\"p\",\"e8ed3798c6ffebffa08501ac39e271662bfd160f688f94c45d692d8767dd345a\",\"\",\"mention\"],[\"t\",\"bitcoin\"],[\"t\",\"bitcoin\"]]}";
+    client_send_event(client, json);
+
+    return 0;
+}

bindings/nostr-sdk-c/examples/keys.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+#include <string.h>
+
+#include <nostr_sdk.h>
+
+int main() {
+    // Generate keys
+    const Keys* keys = keys_generate();
+    printf("Keys generated.\n");
+
+    const char* public_key = keys_public_key(keys);
+    printf("Public key: %s\n", public_key);
+
+    return 0;
+}

bindings/nostr-sdk-c/justfile

@@ -0,0 +1,10 @@
+#!/usr/bin/env just --justfile
+
+build:
+    cargo build --release
+
+examples: build
+    mkdir -p bin/
+    gcc examples/keys.c -o bin/keys -I include/ -L ../../target/release/ -lnostr_sdk_c -lpthread -ldl -lm -lrt
+    gcc examples/client.c -o bin/client -I include/ -L ../../target/release/ -lnostr_sdk_c -lpthread -ldl -lm -lrt
+

bindings/nostr-sdk-c/src/client/mod.rs

@@ -0,0 +1,43 @@
+// Copyright (c) 2022-2023 Yuki Kishimoto
+// Copyright (c) 2023-2024 Rust Nostr Developers
+// Distributed under the MIT software license
+
+use std::ffi::{c_char, CStr};
+
+use nostr_sdk::client;
+use nostr_sdk::nostr::{Event, JsonUtil};
+
+use crate::RUNTIME;
+
+pub struct Client {
+    inner: client::Client,
+}
+
+#[no_mangle]
+pub extern "C" fn client_without_signer() -> *const Client {
+    Box::into_raw(Box::new(Client {
+        inner: client::Client::default(),
+    }))
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn client_add_relay(client: &Client, url: *const c_char) -> bool {
+    RUNTIME.block_on(async {
+        let url: &str = CStr::from_ptr(url).to_str().unwrap();
+        client.inner.add_relay(url).await.unwrap()
+    })
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn client_connect(client: &Client) {
+    RUNTIME.block_on(async { client.inner.connect().await })
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn client_send_event(client: &Client, json: *const c_char) {
+    RUNTIME.block_on(async {
+        let json: &str = CStr::from_ptr(json).to_str().unwrap();
+        let event = Event::from_json(json).unwrap();
+        client.inner.send_event(event).await.unwrap();
+    })
+}

bindings/nostr-sdk-c/src/error.rs

@@ -0,0 +1,26 @@
+// Copyright (c) 2022-2023 Yuki Kishimoto
+// Copyright (c) 2023-2024 Rust Nostr Developers
+// Distributed under the MIT software license
+
+// pub enum CResult {
+//     code: i32,
+//     message: *const c_char,
+//     value: *const c_char, // Change type as needed for different results
+// }
+
+#[repr(C)]
+pub struct CError {
+    message: String,
+}
+
+pub type Result<T> = core::result::Result<T, CError>;
+
+#[inline(always)]
+pub fn into_err<E>(error: E) -> CError
+where
+    E: std::error::Error,
+{
+    CError {
+        message: error.to_string(),
+    }
+}

bindings/nostr-sdk-cpp/src/lib.rs → bindings/nostr-sdk-c/src/lib.rs

@@ -2,24 +2,27 @@
 // Copyright (c) 2023-2024 Rust Nostr Developers
 // Distributed under the MIT software license
 
+use std::ffi::{c_char, CString};
 use std::sync::LazyLock;
 
 use tokio::runtime::Runtime;
 
 pub mod client;
+pub mod error;
 pub mod logger;
 pub mod protocol;
 
 static RUNTIME: LazyLock<Runtime> =
     LazyLock::new(|| Runtime::new().expect("failed to create tokio runtime"));
 
-pub fn git_hash_version() -> String {
-    option_env!("GIT_HASH").unwrap_or_default().to_owned()
+#[inline]
+fn get_git_hash() -> &'static str {
+    option_env!("GIT_HASH").unwrap_or_default()
 }
 
-#[cxx::bridge]
-mod ffi {
-    extern "Rust" {
-        fn git_hash_version() -> String;
-    }
+#[no_mangle]
+pub extern "C" fn git_hash_version() -> *const c_char {
+    let hash: &str = get_git_hash();
+    let c_string = CString::new(hash).unwrap();
+    c_string.into_raw()
 }