Update dependencies and add database statistics (#23)

Add database statistics in a new `Stats` type

Also bundles a few other changes:

- Switch from `gcc` crate to `cc` for building lmdb
- Bump `bitflags` crate to 1.0
- Bump minimum required `rustc` from `1.8` to `1.20`

This is a breaking change.

.travis.yml

@@ -9,7 +9,7 @@ os:
   - osx
 
 rust:
-- 1.8.0
+- 1.20.0
 - stable
 - nightly
 

Cargo.toml

@@ -23,11 +23,11 @@ members = [
 ]
 
 [dependencies]
-bitflags = "0.9"
+bitflags = "1"
 libc = "0.2"
 lmdb-sys = { version = "0.7.2", path = "lmdb-sys" }
 
 [dev-dependencies]
-rand = "0.3"
+rand = "0.4"
 tempdir = "0.3"
 byteorder = "1.0"

README.md

@@ -22,4 +22,4 @@ cargo build
 * [x] Cursors.
 * [x] Zero-copy put API.
 * [x] Nested transactions.
-* [ ] Database statistics.
+* [x] Database statistics.

lmdb-sys/Cargo.toml

@@ -20,5 +20,4 @@ libc = "0.2"
 
 [build-dependencies]
 pkg-config = "0.3"
-# https://github.com/alexcrichton/gcc-rs/issues/240
-gcc = "=0.3.51"
+cc = "1"

lmdb-sys/build.rs

@@ -1,5 +1,5 @@
 extern crate pkg_config;
-extern crate gcc;
+extern crate cc;
 
 use std::env;
 use std::path::PathBuf;
@@ -11,7 +11,7 @@ fn main() {
     lmdb.push("liblmdb");
 
     if !pkg_config::find_library("liblmdb").is_ok() {
-        gcc::Config::new()
+        cc::Build::new()
                     .file(lmdb.join("mdb.c"))
                     .file(lmdb.join("midl.c"))
                     // https://github.com/LMDB/lmdb/blob/LMDB_0.9.21/libraries/liblmdb/Makefile#L25

src/cursor.rs

@@ -349,7 +349,7 @@ mod test {
     fn test_get_dup() {
         let dir = TempDir::new("test").unwrap();
         let env = Environment::new().open(dir.path()).unwrap();
-        let db = env.create_db(None, DUP_SORT).unwrap();
+        let db = env.create_db(None, DatabaseFlags::DUP_SORT).unwrap();
 
         let mut txn = env.begin_rw_txn().unwrap();
         txn.put(db, b"key1", b"val1", WriteFlags::empty()).unwrap();
@@ -395,7 +395,7 @@ mod test {
     fn test_get_dupfixed() {
         let dir = TempDir::new("test").unwrap();
         let env = Environment::new().open(dir.path()).unwrap();
-        let db = env.create_db(None, DUP_SORT | DUP_FIXED).unwrap();
+        let db = env.create_db(None, DatabaseFlags::DUP_SORT | DatabaseFlags::DUP_FIXED).unwrap();
 
         let mut txn = env.begin_rw_txn().unwrap();
         txn.put(db, b"key1", b"val1", WriteFlags::empty()).unwrap();
@@ -449,7 +449,7 @@ mod test {
     fn test_iter_dup() {
         let dir = TempDir::new("test").unwrap();
         let env = Environment::new().open(dir.path()).unwrap();
-        let db = env.create_db(None, DUP_SORT).unwrap();
+        let db = env.create_db(None, DatabaseFlags::DUP_SORT).unwrap();
 
         let items: Vec<(&[u8], &[u8])> = vec!((b"a", b"1"),
                                               (b"a", b"2"),

src/environment.rs

@@ -1,5 +1,5 @@
 use libc::{c_uint, size_t};
-use std::{fmt, ptr, result};
+use std::{fmt, ptr, result, mem};
 use std::ffi::CString;
 #[cfg(unix)]
 use std::os::unix::ffi::OsStrExt;
@@ -35,6 +35,11 @@ pub struct Environment {
     dbi_open_mutex: Mutex<()>,
 }
 
+/// Database statistics
+///
+/// Contains information about the size and layout of an LMDB database
+pub struct Stat(ffi::MDB_stat);
+
 impl Environment {
 
     /// Creates a new builder for specifying options for opening an LMDB environment.
@@ -151,6 +156,53 @@ impl Environment {
     pub unsafe fn close_db(&mut self, db: Database) {
         ffi::mdb_dbi_close(self.env, db.dbi());
     }
+
+    /// Get database statistics.
+    pub fn stat(&self) -> Result<Stat> {
+        unsafe {
+            let mut stat = Stat(mem::zeroed());
+            lmdb_try!(ffi::mdb_env_stat(self.env(), &mut stat.0));
+            Ok(stat)
+        }
+    }
+}
+
+impl Stat {
+    /// Size of database in bytes.
+    #[inline]
+    pub fn size(&self) -> u32 {
+        self.0.ms_psize
+    }
+
+    /// Height of B-tree.
+    #[inline]
+    pub fn depth(&self) -> u32 {
+        self.0.ms_depth
+    }
+
+    /// Number of internal (non-leaf) pages.
+    #[inline]
+    pub fn branch_pages(&self) -> usize {
+        self.0.ms_branch_pages
+    }
+
+    /// Number of lead pages.
+    #[inline]
+    pub fn leaf_pages(&self) -> usize {
+        self.0.ms_leaf_pages
+    }
+
+    /// Number of overflow pages.
+    #[inline]
+    pub fn overflow_pages(&self) -> usize {
+        self.0.ms_overflow_pages
+    }
+
+    /// Number of data items.
+    #[inline]
+    pub fn entries(&self) -> usize {
+        self.0.ms_entries
+    }
 }
 
 unsafe impl Send for Environment {}
@@ -285,7 +337,7 @@ mod test {
         let dir = TempDir::new("test").unwrap();
 
         // opening non-existent env with read-only should fail
-        assert!(Environment::new().set_flags(READ_ONLY)
+        assert!(Environment::new().set_flags(EnvironmentFlags::READ_ONLY)
                                   .open(dir.path())
                                   .is_err());
 
@@ -293,7 +345,7 @@ mod test {
         assert!(Environment::new().open(dir.path()).is_ok());
 
         // opening env with read-only should succeed
-        assert!(Environment::new().set_flags(READ_ONLY)
+        assert!(Environment::new().set_flags(EnvironmentFlags::READ_ONLY)
                                   .open(dir.path())
                                   .is_ok());
     }
@@ -310,7 +362,7 @@ mod test {
         }
 
         { // read-only environment
-            let env = Environment::new().set_flags(READ_ONLY)
+            let env = Environment::new().set_flags(EnvironmentFlags::READ_ONLY)
                                         .open(dir.path())
                                         .unwrap();
 
@@ -360,7 +412,7 @@ mod test {
             let env = Environment::new().open(dir.path()).unwrap();
             assert!(env.sync(true).is_ok());
         } {
-            let env = Environment::new().set_flags(READ_ONLY)
+            let env = Environment::new().set_flags(EnvironmentFlags::READ_ONLY)
                                         .open(dir.path())
                                         .unwrap();
             assert!(env.sync(true).is_err());

src/lib.rs

@@ -21,7 +21,7 @@ pub use cursor::{
     IterDup,
 };
 pub use database::Database;
-pub use environment::{Environment, EnvironmentBuilder};
+pub use environment::{Environment, Stat, EnvironmentBuilder};
 pub use error::{Error, Result};
 pub use flags::*;
 pub use transaction::{
@@ -107,7 +107,7 @@ mod test_utils {
             builder.set_map_size(1_000_000);
             builder.open(dir.path()).expect("open lmdb env")
         };
-        let index = env.create_db(None, DUP_SORT).expect("open index db");
+        let index = env.create_db(None, DatabaseFlags::DUP_SORT).expect("open index db");
 
         for height in 0..1000 {
             let mut value = [0u8; 8];