Revert "remove set_options_from_string (incorrectly named and wrong implementation)"

This reverts commit 0ca3535. The restored
body calls the current ffi_util::convert_rocksdb_error, as error_message no
longer exists.

Signed-off-by: Jason Volk <jason@zemos.net>

Author: jevolk

src/db_options.rs

@@ -1118,6 +1118,34 @@ impl Options {
         }
     }
 
+    /// Updates DBOptions with values parsed from a string.
+    ///
+    /// See official [wiki](
+    /// https://github.com/facebook/rocksdb/wiki/Option-String-and-Option-Map#option-string)
+    /// for more information.
+    pub fn set_options_from_string(&mut self, string: impl CStrLike) -> Result<&mut Self, Error> {
+        let c_string = string.into_c_string().unwrap();
+        let mut err: *mut c_char = null_mut();
+        let err_ptr: *mut *mut c_char = &raw mut err;
+        unsafe {
+            ffi::rocksdb_get_options_from_string(
+                self.inner,
+                c_string.as_ptr(),
+                self.inner,
+                err_ptr,
+            );
+        }
+
+        if err.is_null() {
+            Ok(self)
+        } else {
+            Err(Error::new(format!(
+                "Could not set options from string: {}",
+                crate::ffi_util::convert_rocksdb_error(err)
+            )))
+        }
+    }
+
     /// By default, RocksDB uses only one background thread for flush and
     /// compaction. Calling this function will set it up such that total of
     /// `total_threads` is used. Good value for `total_threads` is the number of

tests/test_rocksdb_options.rs

@@ -588,6 +588,31 @@ fn test_set_ttl() {
     }
 }
 
+#[test]
+fn test_set_options_from_string() {
+    let path = DBPath::new("_set_options_from_string");
+    {
+        let mut opts = Options::default();
+        opts.create_if_missing(true);
+        opts.set_options_from_string("compaction_pri=kOldestSmallestSeqFirst")
+            .expect("option compaction_pri is set");
+        let _db = DB::open(&opts, &path).unwrap();
+    }
+}
+
+#[test]
+#[should_panic(expected = "Could not set options from string: ")]
+fn test_set_options_from_string_failure() {
+    let path = DBPath::new("_set_options_from_string");
+    {
+        let mut opts = Options::default();
+        opts.create_if_missing(true);
+        opts.set_options_from_string("compaction_prikOldestSmallestSeqFirst")
+            .unwrap();
+        let _db = DB::open(&opts, &path).unwrap();
+    }
+}
+
 #[test]
 fn test_set_ratelimiter() {
     let path = DBPath::new("_set_ratelimiter");