add missing filter.rs

src/filter.rs

@@ -0,0 +1,136 @@
+use crate::bindings;
+use std::ffi::CString;
+use std::os::raw::c_char;
+use std::ptr::null_mut;
+
+#[derive(Debug)]
+pub struct Filter {
+    data: bindings::ndb_filter,
+}
+
+impl bindings::ndb_filter {
+    fn as_ptr(&self) -> *const bindings::ndb_filter {
+        self as *const bindings::ndb_filter
+    }
+}
+
+impl Filter {
+    pub fn new() -> Filter {
+        let null = std::ptr::null_mut();
+        let mut filter_data = bindings::ndb_filter {
+            elem_buf: bindings::cursor {
+                start: null,
+                p: null,
+                end: null,
+            },
+            data_buf: bindings::cursor {
+                start: null,
+                p: null,
+                end: null,
+            },
+            num_elements: 0,
+            current: std::ptr::null_mut(),
+            elements: [
+                null_mut(),
+                null_mut(),
+                null_mut(),
+                null_mut(),
+                null_mut(),
+                null_mut(),
+                null_mut(),
+            ],
+        };
+
+        unsafe {
+            bindings::ndb_filter_init(&mut filter_data as *mut bindings::ndb_filter);
+        };
+
+        Self { data: filter_data }
+    }
+
+    pub fn as_ptr(&self) -> *const bindings::ndb_filter {
+        return self.data.as_ptr();
+    }
+
+    pub fn as_mut_ptr(&self) -> *mut bindings::ndb_filter {
+        return self.data.as_ptr() as *mut bindings::ndb_filter;
+    }
+
+    fn add_int_element(&self, i: u64) {
+        unsafe { bindings::ndb_filter_add_int_element(self.as_mut_ptr(), i) };
+    }
+
+    fn add_str_element(&self, s: &str) {
+        let c_str = CString::new(s).expect("string to cstring conversion failed");
+        unsafe {
+            bindings::ndb_filter_add_str_element(self.as_mut_ptr(), c_str.as_ptr());
+        };
+    }
+
+    fn add_id_element(&self, id: &[u8; 32]) {
+        let ptr: *const ::std::os::raw::c_uchar = id.as_ptr() as *const ::std::os::raw::c_uchar;
+        unsafe {
+            bindings::ndb_filter_add_id_element(self.as_mut_ptr(), ptr);
+        };
+    }
+
+    fn start_kind_field(&self) {
+        unsafe {
+            bindings::ndb_filter_start_field(
+                self.as_mut_ptr(),
+                bindings::ndb_filter_fieldtype_NDB_FILTER_KINDS,
+            )
+        };
+    }
+
+    fn end_field(&self) {
+        unsafe { bindings::ndb_filter_end_field(self.as_mut_ptr()) }
+    }
+
+    pub fn authors(self, authors: Vec<[u8; 32]>) -> Filter {
+        unsafe {
+            bindings::ndb_filter_start_field(
+                self.as_mut_ptr(),
+                bindings::ndb_filter_fieldtype_NDB_FILTER_AUTHORS,
+            );
+        };
+
+        for author in authors {
+            self.add_id_element(&author);
+        }
+
+        self.end_field();
+
+        self
+    }
+
+    fn start_tag_field(&self, tag: char) {
+        unsafe {
+            bindings::ndb_filter_start_tag_field(self.as_mut_ptr(), tag as u8 as c_char);
+        }
+    }
+
+    pub fn kinds(self, kinds: Vec<u64>) -> Filter {
+        self.start_kind_field();
+        for kind in kinds {
+            self.add_int_element(kind);
+        }
+        self.end_field();
+        self
+    }
+
+    pub fn hashtags(self, tags: Vec<String>) -> Filter {
+        self.start_tag_field('t');
+        for tag in tags {
+            self.add_str_element(&tag);
+        }
+        self.end_field();
+        self
+    }
+}
+
+impl Drop for Filter {
+    fn drop(&mut self) {
+        unsafe { bindings::ndb_filter_destroy(self.as_mut_ptr()) };
+    }
+}