Compile lmdb with opt level O2

LMDB segfaults reliably with newer GCC versions when compiled with O3.
Regression test included.

fixes #21

.travis.yml

@@ -17,4 +17,5 @@ script:
   - cargo build --verbose
   - if [[ $TRAVIS_RUST_VERSION = nightly* ]]; then
       env RUST_BACKTRACE=1 cargo test --all -v;
+      env RUST_BACKTRACE=1 cargo test --all -v --release;
     fi

Cargo.toml

@@ -25,3 +25,4 @@ lmdb-sys = { path = "lmdb-sys" }
 [dev-dependencies]
 rand = "0.3"
 tempdir = "0.3"
+byteorder = "1.0"

lmdb-sys/Cargo.toml

@@ -20,4 +20,4 @@ libc = "0.2"
 
 [build-dependencies]
 pkg-config = "0.3"
-gcc = "0.3"
+gcc = "0.3.53"

lmdb-sys/build.rs

@@ -5,21 +5,17 @@ use std::env;
 use std::path::PathBuf;
 
 fn main() {
-
     let mut lmdb: PathBuf = PathBuf::from(&env::var("CARGO_MANIFEST_DIR").unwrap());
     lmdb.push("lmdb");
     lmdb.push("libraries");
     lmdb.push("liblmdb");
 
-    let mut mdb: PathBuf = lmdb.clone();
-    let mut midl: PathBuf = lmdb.clone();
-
-    mdb.push("mdb.c");
-    midl.push("midl.c");
-
     if !pkg_config::find_library("liblmdb").is_ok() {
-        gcc::compile_library("liblmdb.a",
-                             &[(*mdb).to_str().unwrap(),
-                               (*midl).to_str().unwrap()]);
+        gcc::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
+                   .opt_level(2)
+                   .compile("lmdb.a")
     }
 }

src/lib.rs

@@ -62,6 +62,9 @@ mod transaction;
 #[cfg(test)]
 mod test_utils {
 
+    extern crate byteorder;
+
+    use self::byteorder::{ByteOrder, LittleEndian};
     use tempdir::TempDir;
 
     use super::*;
@@ -88,4 +91,33 @@ mod test_utils {
         }
         (dir, env)
     }
+
+    /// Regression test for https://github.com/danburkert/lmdb-rs/issues/21.
+    /// This test reliably segfaults when run against lmbdb compiled with opt level -O3 and newer
+    /// GCC compilers.
+    #[test]
+    fn issue_21_regression() {
+        const HEIGHT_KEY: [u8; 1] = [0];
+
+        let dir = TempDir::new("test").unwrap();
+
+        let env = {
+            let mut builder = Environment::new();
+            builder.set_max_dbs(2);
+            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");
+
+        for height in 0..1000 {
+            let mut value = [0u8; 8];
+            LittleEndian::write_u64(&mut value, height);
+            let mut tx = env.begin_rw_txn().expect("begin_rw_txn");
+            tx.put(index,
+                   &HEIGHT_KEY,
+                   &value,
+                   WriteFlags::empty()).expect("tx.put");
+            tx.commit().expect("ts.commit")
+        }
+    }
 }