Replace functions::ToResult with ToSql.

src/functions.rs

@@ -54,7 +54,7 @@ use std::ffi::CStr;
 use std::mem;
 use std::ptr;
 use std::slice;
-use libc::{c_int, c_double, c_char, c_void};
+use libc::{c_int, c_char, c_void};
 
 use ffi;
 pub use ffi::sqlite3_context;
@@ -62,97 +62,70 @@ pub use ffi::sqlite3_value;
 pub use ffi::sqlite3_value_type;
 pub use ffi::sqlite3_value_numeric_type;
 
-use types::{Null, FromSql, ValueRef};
+use types::{ToSql, ToSqlOutput, FromSql, ValueRef};
 
 use {Result, Error, Connection, str_to_cstring, InnerConnection};
 
-/// A trait for types that can be converted into the result of an SQL function.
-pub trait ToResult {
-    unsafe fn set_result(&self, ctx: *mut sqlite3_context);
-}
+fn set_result<'a>(ctx: *mut sqlite3_context, result: &ToSqlOutput<'a>) {
+    let value = match *result {
+        ToSqlOutput::Borrowed(v) => v,
+        ToSqlOutput::Owned(ref v) => ValueRef::from(v),
 
-macro_rules! raw_to_impl(
-    ($t:ty, $f:ident) => (
-        impl ToResult for $t {
-            unsafe fn set_result(&self, ctx: *mut sqlite3_context) {
-                ffi::$f(ctx, *self)
+        #[cfg(feature = "blob")]
+        ToSqlOutput::ZeroBlob(len) => {
+            return unsafe { ffi::sqlite3_result_zeroblob(ctx, len) };
         }
-        }
-    )
-);
+    };
 
-raw_to_impl!(c_int, sqlite3_result_int);
-raw_to_impl!(i64, sqlite3_result_int64);
-raw_to_impl!(c_double, sqlite3_result_double);
-
-impl<'a> ToResult for bool {
-    unsafe fn set_result(&self, ctx: *mut sqlite3_context) {
-        if *self {
-            ffi::sqlite3_result_int(ctx, 1)
-        } else {
-            ffi::sqlite3_result_int(ctx, 0)
-        }
-    }
-}
-
-
-impl<'a> ToResult for &'a str {
-    unsafe fn set_result(&self, ctx: *mut sqlite3_context) {
-        let length = self.len();
+    match value {
+        ValueRef::Null => unsafe { ffi::sqlite3_result_null(ctx) },
+        ValueRef::Integer(i) => unsafe { ffi::sqlite3_result_int64(ctx, i) },
+        ValueRef::Real(r) => unsafe { ffi::sqlite3_result_double(ctx, r) },
+        ValueRef::Text(ref s) => unsafe {
+            let length = s.len();
             if length > ::std::i32::MAX as usize {
                 ffi::sqlite3_result_error_toobig(ctx);
-            return;
-        }
-        match str_to_cstring(self) {
-            Ok(c_str) => {
-                ffi::sqlite3_result_text(ctx,
-                                         c_str.as_ptr(),
-                                         length as c_int,
-                                         ffi::SQLITE_TRANSIENT())
-            }
+            } else {
+                let c_str = match str_to_cstring(s) {
+                    Ok(c_str) => c_str,
                     // TODO sqlite3_result_error
-            Err(_) => ffi::sqlite3_result_error_code(ctx, ffi::SQLITE_MISUSE),
+                    Err(_) => return ffi::sqlite3_result_error_code(ctx, ffi::SQLITE_MISUSE),
+                };
+                let destructor = if length > 0 {
+                    ffi::SQLITE_TRANSIENT()
+                } else {
+                    ffi::SQLITE_STATIC()
+                };
+                ffi::sqlite3_result_text(ctx, c_str.as_ptr(), length as c_int, destructor);
             }
-    }
-}
-
-impl ToResult for String {
-    unsafe fn set_result(&self, ctx: *mut sqlite3_context) {
-        (&self[..]).set_result(ctx)
-    }
-}
-
-impl<'a> ToResult for &'a [u8] {
-    unsafe fn set_result(&self, ctx: *mut sqlite3_context) {
-        if self.len() > ::std::i32::MAX as usize {
+        },
+        ValueRef::Blob(ref b) => unsafe {
+            let length = b.len();
+            if length > ::std::i32::MAX as usize {
                 ffi::sqlite3_result_error_toobig(ctx);
-            return;
+            } else if length == 0 {
+                ffi::sqlite3_result_zeroblob(ctx, 0)
+            } else {
+                ffi::sqlite3_result_blob(ctx, b.as_ptr() as *const c_void, length as c_int, ffi::SQLITE_TRANSIENT());
             }
-        ffi::sqlite3_result_blob(ctx,
-                                 mem::transmute(self.as_ptr()),
-                                 self.len() as c_int,
-                                 ffi::SQLITE_TRANSIENT())
+        },
     }
 }
 
-impl ToResult for Vec<u8> {
-    unsafe fn set_result(&self, ctx: *mut sqlite3_context) {
-        (&self[..]).set_result(ctx)
-    }
-}
-
-impl<T: ToResult> ToResult for Option<T> {
-    unsafe fn set_result(&self, ctx: *mut sqlite3_context) {
-        match *self {
-            None => ffi::sqlite3_result_null(ctx),
-            Some(ref t) => t.set_result(ctx),
+unsafe fn report_error(ctx: *mut sqlite3_context, err: &Error) {
+    match err {
+        &Error::SqliteFailure(ref err, ref s) => {
+            ffi::sqlite3_result_error_code(ctx, err.extended_code);
+            if let Some(Ok(cstr)) = s.as_ref().map(|s| str_to_cstring(s)) {
+                ffi::sqlite3_result_error(ctx, cstr.as_ptr(), -1);
+            }
+        }
+        _ => {
+            ffi::sqlite3_result_error_code(ctx, ffi::SQLITE_CONSTRAINT_FUNCTION);
+            if let Ok(cstr) = str_to_cstring(err.description()) {
+                ffi::sqlite3_result_error(ctx, cstr.as_ptr(), -1);
             }
         }
-}
-
-impl ToResult for Null {
-    unsafe fn set_result(&self, ctx: *mut sqlite3_context) {
-        ffi::sqlite3_result_null(ctx)
     }
 }
 
@@ -259,7 +232,7 @@ impl<'a> Context<'a> {
 /// `A` is the type of the aggregation context and `T` is the type of the final result.
 /// Implementations should be stateless.
 pub trait Aggregate<A, T>
-    where T: ToResult
+    where T: ToSql
 {
     /// Initializes the aggregation context. Will be called prior to the first call
     /// to `step()` to set up the context for an invocation of the function. (Note:
@@ -316,7 +289,7 @@ impl Connection {
                                         x_func: F)
                                         -> Result<()>
         where F: FnMut(&Context) -> Result<T>,
-              T: ToResult
+              T: ToSql
     {
         self.db.borrow_mut().create_scalar_function(fn_name, n_arg, deterministic, x_func)
     }
@@ -333,7 +306,7 @@ impl Connection {
                                               aggr: D)
                                               -> Result<()>
         where D: Aggregate<A, T>,
-              T: ToResult
+              T: ToSql
     {
         self.db
             .borrow_mut()
@@ -361,13 +334,13 @@ impl InnerConnection {
                                     x_func: F)
                                     -> Result<()>
         where F: FnMut(&Context) -> Result<T>,
-              T: ToResult
+              T: ToSql
     {
         unsafe extern "C" fn call_boxed_closure<F, T>(ctx: *mut sqlite3_context,
                                                       argc: c_int,
                                                       argv: *mut *mut sqlite3_value)
             where F: FnMut(&Context) -> Result<T>,
-                  T: ToResult
+                  T: ToSql
         {
             let ctx = Context {
                 ctx: ctx,
@@ -375,20 +348,14 @@ impl InnerConnection {
             };
             let boxed_f: *mut F = mem::transmute(ffi::sqlite3_user_data(ctx.ctx));
             assert!(!boxed_f.is_null(), "Internal error - null function pointer");
-            match (*boxed_f)(&ctx) {
-                Ok(r) => r.set_result(ctx.ctx),
-                Err(Error::SqliteFailure(err, s)) => {
-                    ffi::sqlite3_result_error_code(ctx.ctx, err.extended_code);
-                    if let Some(Ok(cstr)) = s.map(|s| str_to_cstring(&s)) {
-                        ffi::sqlite3_result_error(ctx.ctx, cstr.as_ptr(), -1);
-                    }
-                }
-                Err(err) => {
-                    ffi::sqlite3_result_error_code(ctx.ctx, ffi::SQLITE_CONSTRAINT_FUNCTION);
-                    if let Ok(cstr) = str_to_cstring(err.description()) {
-                        ffi::sqlite3_result_error(ctx.ctx, cstr.as_ptr(), -1);
-                    }
-                }
+
+            let t = (*boxed_f)(&ctx);
+            let t = t.as_ref().map(|t| ToSql::to_sql(t));
+
+            match t {
+                Ok(Ok(ref value)) => set_result(ctx.ctx, value),
+                Ok(Err(err)) => report_error(ctx.ctx, &err),
+                Err(err) => report_error(ctx.ctx, err),
             }
         }
 
@@ -419,7 +386,7 @@ impl InnerConnection {
                                           aggr: D)
                                           -> Result<()>
         where D: Aggregate<A, T>,
-              T: ToResult
+              T: ToSql
     {
         unsafe fn aggregate_context<A>(ctx: *mut sqlite3_context,
                                        bytes: usize)
@@ -431,28 +398,11 @@ impl InnerConnection {
             Some(pac)
         }
 
-        unsafe fn report_aggregate_error(ctx: *mut sqlite3_context, err: Error) {
-            match err {
-                Error::SqliteFailure(err, s) => {
-                    ffi::sqlite3_result_error_code(ctx, err.extended_code);
-                    if let Some(Ok(cstr)) = s.map(|s| str_to_cstring(&s)) {
-                        ffi::sqlite3_result_error(ctx, cstr.as_ptr(), -1);
-                    }
-                }
-                _ => {
-                    ffi::sqlite3_result_error_code(ctx, ffi::SQLITE_CONSTRAINT_FUNCTION);
-                    if let Ok(cstr) = str_to_cstring(err.description()) {
-                        ffi::sqlite3_result_error(ctx, cstr.as_ptr(), -1);
-                    }
-                }
-            }
-        }
-
         unsafe extern "C" fn call_boxed_step<A, D, T>(ctx: *mut sqlite3_context,
                                                       argc: c_int,
                                                       argv: *mut *mut sqlite3_value)
             where D: Aggregate<A, T>,
-                  T: ToResult
+                  T: ToSql
         {
             let boxed_aggr: *mut D = mem::transmute(ffi::sqlite3_user_data(ctx));
             assert!(!boxed_aggr.is_null(),
@@ -477,13 +427,13 @@ impl InnerConnection {
 
             match (*boxed_aggr).step(&mut ctx, &mut **pac) {
                 Ok(_) => {}
-                Err(err) => report_aggregate_error(ctx.ctx, err),
+                Err(err) => report_error(ctx.ctx, &err),
             };
         }
 
         unsafe extern "C" fn call_boxed_final<A, D, T>(ctx: *mut sqlite3_context)
             where D: Aggregate<A, T>,
-                  T: ToResult
+                  T: ToSql
         {
             let boxed_aggr: *mut D = mem::transmute(ffi::sqlite3_user_data(ctx));
             assert!(!boxed_aggr.is_null(),
@@ -503,10 +453,13 @@ impl InnerConnection {
                 None => None,
             };
 
-            match (*boxed_aggr).finalize(a) {
-                Ok(r) => r.set_result(ctx),
-                Err(err) => report_aggregate_error(ctx, err),
-            };
+            let t = (*boxed_aggr).finalize(a);
+            let t = t.as_ref().map(|t| ToSql::to_sql(t));
+            match t {
+                Ok(Ok(ref value)) => set_result(ctx, value),
+                Ok(Err(err)) => report_error(ctx, &err),
+                Err(err) => report_error(ctx, err),
+            }
         }
 
         let boxed_aggr: *mut D = Box::into_raw(Box::new(aggr));