Merge pull request #247 from ekmartin/ek/properties

Add property getters

src/db.rs

@@ -1392,6 +1392,118 @@ impl DB {
             ))
         })
     }
+
+    /// Retrieves a RocksDB property by name.
+    ///
+    /// For a full list of properties, see
+    /// https://github.com/facebook/rocksdb/blob/08809f5e6cd9cc4bc3958dd4d59457ae78c76660/include/rocksdb/db.h#L428-L634
+    pub fn property_value(&self, name: &str) -> Result<Option<String>, Error> {
+        let prop_name = match CString::new(name) {
+            Ok(c) => c,
+            Err(e) => {
+                return Err(Error::new(format!(
+                    "Failed to convert property name to CString: {}",
+                    e
+                )));
+            }
+        };
+
+        unsafe {
+            let value = ffi::rocksdb_property_value(self.inner, prop_name.as_ptr());
+            if value.is_null() {
+                return Ok(None);
+            }
+
+            let str_value = match CStr::from_ptr(value).to_str() {
+                Ok(s) => s.to_owned(),
+                Err(e) => {
+                    return Err(Error::new(format!(
+                        "Failed to convert property value to string: {}",
+                        e
+                    )));
+                }
+            };
+
+            libc::free(value as *mut c_void);
+            Ok(Some(str_value))
+        }
+    }
+
+    /// Retrieves a RocksDB property by name, for a specific column family.
+    ///
+    /// For a full list of properties, see
+    /// https://github.com/facebook/rocksdb/blob/08809f5e6cd9cc4bc3958dd4d59457ae78c76660/include/rocksdb/db.h#L428-L634
+    pub fn property_value_cf(&self, cf: ColumnFamily, name: &str) -> Result<Option<String>, Error> {
+        let prop_name = match CString::new(name) {
+            Ok(c) => c,
+            Err(e) => {
+                return Err(Error::new(format!(
+                    "Failed to convert property name to CString: {}",
+                    e
+                )));
+            }
+        };
+
+        unsafe {
+            let value = ffi::rocksdb_property_value_cf(self.inner, cf.inner, prop_name.as_ptr());
+            if value.is_null() {
+                return Ok(None);
+            }
+
+            let str_value = match CStr::from_ptr(value).to_str() {
+                Ok(s) => s.to_owned(),
+                Err(e) => {
+                    return Err(Error::new(format!(
+                        "Failed to convert property value to string: {}",
+                        e
+                    )));
+                }
+            };
+
+            libc::free(value as *mut c_void);
+            Ok(Some(str_value))
+        }
+    }
+
+    /// Retrieves a RocksDB property and casts it to an integer.
+    ///
+    /// For a full list of properties that return int values, see
+    /// https://github.com/facebook/rocksdb/blob/08809f5e6cd9cc4bc3958dd4d59457ae78c76660/include/rocksdb/db.h#L654-L689
+    pub fn property_int_value(&self, name: &str) -> Result<Option<u64>, Error> {
+        match self.property_value(name) {
+            Ok(Some(value)) => match value.parse::<u64>() {
+                Ok(int_value) => Ok(Some(int_value)),
+                Err(e) => Err(Error::new(format!(
+                    "Failed to convert property value to int: {}",
+                    e
+                ))),
+            },
+            Ok(None) => Ok(None),
+            Err(e) => Err(e),
+        }
+    }
+
+    /// Retrieves a RocksDB property for a specific column family and casts it to an integer.
+    ///
+    /// For a full list of properties that return int values, see
+    /// https://github.com/facebook/rocksdb/blob/08809f5e6cd9cc4bc3958dd4d59457ae78c76660/include/rocksdb/db.h#L654-L689
+    pub fn property_int_value_cf(
+        &self,
+        cf: ColumnFamily,
+        name: &str,
+    ) -> Result<Option<u64>, Error> {
+        match self.property_value_cf(cf, name) {
+            Ok(Some(value)) => match value.parse::<u64>() {
+                Ok(int_value) => Ok(Some(int_value)),
+                Err(e) => Err(Error::new(format!(
+                    "Failed to convert property value to int: {}",
+                    e
+                ))),
+            },
+            Ok(None) => Ok(None),
+            Err(e) => Err(e),
+        }
+    }
 }
 
 impl WriteBatch {

tests/test_property.rs

@@ -0,0 +1,71 @@
+// Copyright 2019 Tyler Neely
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+extern crate rocksdb;
+mod util;
+
+use rocksdb::{Options, DB};
+use util::DBPath;
+
+#[test]
+fn property_test() {
+    let n = DBPath::new("_rust_rocksdb_property_test");
+    {
+        let db = DB::open_default(&n).unwrap();
+        let value = db.property_value("rocksdb.stats").unwrap().unwrap();
+
+        assert!(value.contains("Stats"));
+    }
+}
+
+#[test]
+fn property_cf_test() {
+    let n = DBPath::new("_rust_rocksdb_property_cf_test");
+    {
+        let opts = Options::default();
+        let db = DB::open_default(&n).unwrap();
+        let cf = db.create_cf("cf1", &opts).unwrap();
+        let value = db.property_value_cf(cf, "rocksdb.stats").unwrap().unwrap();
+
+        assert!(value.contains("Stats"));
+    }
+}
+
+#[test]
+fn property_int_test() {
+    let n = DBPath::new("_rust_rocksdb_property_int_test");
+    {
+        let db = DB::open_default(&n).unwrap();
+        let value = db
+            .property_int_value("rocksdb.estimate-live-data-size")
+            .unwrap();
+
+        assert!(value == Some(0));
+    }
+}
+
+#[test]
+fn property_int_cf_test() {
+    let n = DBPath::new("_rust_rocksdb_property_int_cf_test");
+    {
+        let opts = Options::default();
+        let db = DB::open_default(&n).unwrap();
+        let cf = db.create_cf("cf1", &opts).unwrap();
+        let total_keys = db
+            .property_int_value_cf(cf, "rocksdb.estimate-num-keys")
+            .unwrap();
+
+        assert!(total_keys == Some(0));
+    }
+}