Define API for vfs modules extensions

Cargo.lock

@@ -336,16 +336,16 @@ checksum = "18758054972164c3264f7c8386f5fc6da6114cb46b619fd365d4e3b2dc3ae487"
 
 [[package]]
 name = "chrono"
-version = "0.4.39"
+version = "0.4.40"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7e36cc9d416881d2e24f9a963be5fb1cd90966419ac844274161d10488b3e825"
+checksum = "1a7964611d71df112cb1730f2ee67324fcf4d0fc6606acbbe9bfe06df124637c"
 dependencies = [
  "android-tzdata",
  "iana-time-zone",
  "js-sys",
  "num-traits",
  "wasm-bindgen",
- "windows-targets 0.52.6",
+ "windows-link",
 ]
 
 [[package]]
@@ -1043,8 +1043,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "43a49c392881ce6d5c3b8cb70f98717b7c07aabbdff06687b9030dbfbe2725f8"
 dependencies = [
  "cfg-if",
+ "js-sys",
  "libc",
  "wasi 0.13.3+wasi-0.2.2",
+ "wasm-bindgen",
  "windows-targets 0.52.6",
 ]
 
@@ -1709,6 +1711,8 @@ dependencies = [
 name = "limbo_ext"
 version = "0.0.16"
 dependencies = [
+ "chrono",
+ "getrandom 0.3.1",
  "limbo_macros",
 ]
 
@@ -3614,6 +3618,12 @@ dependencies = [
  "windows-targets 0.52.6",
 ]
 
+[[package]]
+name = "windows-link"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6dccfd733ce2b1753b03b6d3c65edf020262ea35e20ccdf3e288043e6dd620e3"
+
 [[package]]
 name = "windows-sys"
 version = "0.45.0"

extensions/core/Cargo.toml

@@ -12,4 +12,6 @@ core_only = []
 static = []
 
 [dependencies]
+chrono = "0.4.40"
+getrandom = { version = "0.3.1", features = ["wasm_js"] }
 limbo_macros = { workspace = true }

extensions/core/src/lib.rs

@@ -1,4 +1,5 @@
 mod types;
+mod vfs_modules;
 pub use limbo_macros::{register_extension, scalar, AggregateDerive, VTabModuleDerive};
 use std::{
     fmt::Display,

extensions/core/src/vfs_modules.rs

@@ -0,0 +1,113 @@
+use crate::{ExtResult, ResultCode};
+use std::ffi::{c_char, c_void};
+
+#[cfg(not(target_family = "wasm"))]
+pub trait VfsExtension: Default {
+    const NAME: &'static str;
+    type File: VfsFile;
+    fn open_file(&self, path: &str, flags: i32, direct: bool) -> ExtResult<Self::File>;
+    fn run_once(&self) -> ExtResult<()> {
+        Ok(())
+    }
+    fn close(&self, _file: Self::File) -> ExtResult<()> {
+        Ok(())
+    }
+    fn generate_random_number(&self) -> i64 {
+        let mut buf = [0u8; 8];
+        getrandom::fill(&mut buf).unwrap();
+        i64::from_ne_bytes(buf)
+    }
+    fn get_current_time(&self) -> String {
+        chrono::Local::now().format("%Y-%m-%d %H:%M:%S").to_string()
+    }
+}
+
+#[cfg(not(target_family = "wasm"))]
+pub trait VfsFile: Sized {
+    fn lock(&mut self, _exclusive: bool) -> ExtResult<()> {
+        Ok(())
+    }
+    fn unlock(&self) -> ExtResult<()> {
+        Ok(())
+    }
+    fn read(&mut self, buf: &mut [u8], count: usize, offset: i64) -> ExtResult<i32>;
+    fn write(&mut self, buf: &[u8], count: usize, offset: i64) -> ExtResult<i32>;
+    fn sync(&self) -> ExtResult<()>;
+    fn size(&self) -> i64;
+}
+
+#[repr(C)]
+pub struct VfsImpl {
+    pub name: *const c_char,
+    pub vfs: *const c_void,
+    pub open: VfsOpen,
+    pub close: VfsClose,
+    pub read: VfsRead,
+    pub write: VfsWrite,
+    pub sync: VfsSync,
+    pub lock: VfsLock,
+    pub unlock: VfsUnlock,
+    pub size: VfsSize,
+    pub run_once: VfsRunOnce,
+    pub current_time: VfsGetCurrentTime,
+    pub gen_random_number: VfsGenerateRandomNumber,
+}
+
+pub type RegisterVfsFn =
+    unsafe extern "C" fn(name: *const c_char, vfs: *const VfsImpl) -> ResultCode;
+
+pub type VfsOpen = unsafe extern "C" fn(
+    ctx: *const c_void,
+    path: *const c_char,
+    flags: i32,
+    direct: bool,
+) -> *const c_void;
+
+pub type VfsClose = unsafe extern "C" fn(file: *const c_void) -> ResultCode;
+
+pub type VfsRead =
+    unsafe extern "C" fn(file: *const c_void, buf: *mut u8, count: usize, offset: i64) -> i32;
+
+pub type VfsWrite =
+    unsafe extern "C" fn(file: *const c_void, buf: *const u8, count: usize, offset: i64) -> i32;
+
+pub type VfsSync = unsafe extern "C" fn(file: *const c_void) -> i32;
+
+pub type VfsLock = unsafe extern "C" fn(file: *const c_void, exclusive: bool) -> ResultCode;
+
+pub type VfsUnlock = unsafe extern "C" fn(file: *const c_void) -> ResultCode;
+
+pub type VfsSize = unsafe extern "C" fn(file: *const c_void) -> i64;
+
+pub type VfsRunOnce = unsafe extern "C" fn(file: *const c_void) -> ResultCode;
+
+pub type VfsGetCurrentTime = unsafe extern "C" fn() -> *const c_char;
+
+pub type VfsGenerateRandomNumber = unsafe extern "C" fn() -> i64;
+
+#[repr(C)]
+pub struct VfsFileImpl {
+    pub file: *const c_void,
+    pub vfs: *const VfsImpl,
+}
+
+impl VfsFileImpl {
+    pub fn new(file: *const c_void, vfs: *const VfsImpl) -> ExtResult<Self> {
+        if file.is_null() || vfs.is_null() {
+            return Err(ResultCode::Error);
+        }
+        Ok(Self { file, vfs })
+    }
+}
+
+impl Drop for VfsFileImpl {
+    fn drop(&mut self) {
+        if self.vfs.is_null() || self.file.is_null() {
+            return;
+        }
+        let vfs = unsafe { &*self.vfs };
+        unsafe {
+            (vfs.close)(self.file);
+        }
+    }
+}