Add SQLite support, fix un-thread-safe DB caches, small performance f… (#172)

* Add SQLite support, fix un-thread-safe DB caches, small performance fixes

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

* add SQLite licenses to README

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

* appease the linter, and fix my dumbass-ery

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

* make requested changes

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

* add back comment

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

1 files changed, 65 insertions, 0 deletions

diff --git a/vendor/modernc.org/libc/ioutil_darwin.go b/vendor/modernc.org/libc/ioutil_darwin.go
new file mode 100644
index 000000000..1628bfa3c
--- /dev/null
+++ b/vendor/modernc.org/libc/ioutil_darwin.go
@@ -0,0 +1,65 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE-GO file.
+
+// Modifications Copyright 2020 The Libc Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package libc // import "modernc.org/libc"
+
+import (
+	"fmt"
+	"os"
+	"sync"
+	"time"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+)
+
+// Random number state.
+// We generate random temporary file names so that there's a good
+// chance the file doesn't exist yet - keeps the number of tries in
+// TempFile to a minimum.
+var randState uint32
+var randStateMu sync.Mutex
+
+func reseed() uint32 {
+	return uint32(time.Now().UnixNano() + int64(os.Getpid()))
+}
+
+func nextRandom(x uintptr) {
+	randStateMu.Lock()
+	r := randState
+	if r == 0 {
+		r = reseed()
+	}
+	r = r*1664525 + 1013904223 // constants from Numerical Recipes
+	randState = r
+	randStateMu.Unlock()
+	copy((*RawMem)(unsafe.Pointer(x))[:6:6], fmt.Sprintf("%06d", int(1e9+r%1e9)%1e6))
+}
+
+func tempFile(s, x uintptr) (fd int, err error) {
+	const maxTry = 10000
+	nconflict := 0
+	for i := 0; i < maxTry; i++ {
+		nextRandom(x)
+		if fd, err = unix.Open(GoString(s), os.O_RDWR|os.O_CREATE|os.O_EXCL, 0600); err == nil {
+			return fd, nil
+		}
+
+		if !os.IsExist(err) {
+			return -1, err
+		}
+
+		if nconflict++; nconflict > 10 {
+			randStateMu.Lock()
+			randState = reseed()
+			nconflict = 0
+			randStateMu.Unlock()
+		}
+	}
+	return -1, err
+}