Introduce to_sqlite_error

643c0f699f
One small step to support creating loadable extension

src/error.rs

@@ -443,3 +443,25 @@ pub fn check(code: c_int) -> Result<()> {
         Ok(())
     }
 }
+
+/// Transform Rust error to SQLite error (message and code).
+/// # Safety
+/// This function is unsafe because it uses raw pointer
+pub unsafe fn to_sqlite_error(
+    e: &Error,
+    err_msg: *mut *mut std::os::raw::c_char,
+) -> std::os::raw::c_int {
+    use crate::util::alloc;
+    match e {
+        Error::SqliteFailure(err, s) => {
+            if let Some(s) = s {
+                *err_msg = alloc(&s);
+            }
+            err.extended_code
+        }
+        err => {
+            *err_msg = alloc(&err.to_string());
+            ffi::SQLITE_ERROR
+        }
+    }
+}

src/lib.rs

@@ -75,7 +75,7 @@ use crate::types::ValueRef;
 
 pub use crate::cache::CachedStatement;
 pub use crate::column::Column;
-pub use crate::error::Error;
+pub use crate::error::{to_sqlite_error, Error};
 pub use crate::ffi::ErrorCode;
 #[cfg(feature = "load_extension")]
 pub use crate::load_extension_guard::LoadExtensionGuard;

src/util/mod.rs

@@ -6,4 +6,4 @@ pub(crate) use small_cstr::SmallCString;
 
 // Doesn't use any modern features or vtab stuff, but is only used by them.
 mod sqlite_string;
-pub(crate) use sqlite_string::SqliteMallocString;
+pub(crate) use sqlite_string::{alloc, SqliteMallocString};

src/util/sqlite_string.rs

@@ -7,6 +7,12 @@ use std::marker::PhantomData;
 use std::os::raw::{c_char, c_int};
 use std::ptr::NonNull;
 
+// Space to hold this string must be obtained
+// from an SQLite memory allocation function
+pub(crate) fn alloc(s: &str) -> *mut c_char {
+    SqliteMallocString::from_str(s).into_raw()
+}
+
 /// A string we own that's allocated on the SQLite heap. Automatically calls
 /// `sqlite3_free` when dropped, unless `into_raw` (or `into_inner`) is called
 /// on it. If constructed from a rust string, `sqlite3_malloc` is used.

src/vtab/mod.rs

@@ -17,10 +17,11 @@ use std::ptr;
 use std::slice;
 
 use crate::context::set_result;
-use crate::error::error_from_sqlite_code;
+use crate::error::{error_from_sqlite_code, to_sqlite_error};
 use crate::ffi;
 pub use crate::ffi::{sqlite3_vtab, sqlite3_vtab_cursor};
 use crate::types::{FromSql, FromSqlError, ToSql, ValueRef};
+use crate::util::alloc;
 use crate::{str_to_cstring, Connection, Error, InnerConnection, Result};
 
 // let conn: Connection = ...;
@@ -964,8 +965,7 @@ where
                     ffi::SQLITE_OK
                 } else {
                     let err = error_from_sqlite_code(rc, None);
-                    *err_msg = alloc(&err.to_string());
+                    to_sqlite_error(&err, err_msg)
-                    rc
                 }
             }
             Err(err) => {
@@ -973,16 +973,7 @@ where
                 ffi::SQLITE_ERROR
             }
         },
-        Err(Error::SqliteFailure(err, s)) => {
+        Err(err) => to_sqlite_error(&err, err_msg),
-            if let Some(s) = s {
-                *err_msg = alloc(&s);
-            }
-            err.extended_code
-        }
-        Err(err) => {
-            *err_msg = alloc(&err.to_string());
-            ffi::SQLITE_ERROR
-        }
     }
 }
 
@@ -1016,8 +1007,7 @@ where
                     ffi::SQLITE_OK
                 } else {
                     let err = error_from_sqlite_code(rc, None);
-                    *err_msg = alloc(&err.to_string());
+                    to_sqlite_error(&err, err_msg)
-                    rc
                 }
             }
             Err(err) => {
@@ -1025,16 +1015,7 @@ where
                 ffi::SQLITE_ERROR
             }
         },
-        Err(Error::SqliteFailure(err, s)) => {
+        Err(err) => to_sqlite_error(&err, err_msg),
-            if let Some(s) = s {
-                *err_msg = alloc(&s);
-            }
-            err.extended_code
-        }
-        Err(err) => {
-            *err_msg = alloc(&err.to_string());
-            ffi::SQLITE_ERROR
-        }
     }
 }
 
@@ -1311,12 +1292,6 @@ unsafe fn result_error<T>(ctx: *mut ffi::sqlite3_context, result: Result<T>) ->
     }
 }
 
-// Space to hold this string must be obtained
-// from an SQLite memory allocation function
-fn alloc(s: &str) -> *mut c_char {
-    crate::util::SqliteMallocString::from_str(s).into_raw()
-}
-
 #[cfg(feature = "array")]
 #[cfg_attr(docsrs, doc(cfg(feature = "array")))]
 pub mod array;