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Diffstat (limited to 'callback.go')
-rw-r--r--callback.go52
1 files changed, 49 insertions, 3 deletions
diff --git a/callback.go b/callback.go
index ee9d40c..e2bf3c6 100644
--- a/callback.go
+++ b/callback.go
@@ -24,29 +24,75 @@ import (
"fmt"
"math"
"reflect"
+ "sync"
"unsafe"
)
//export callbackTrampoline
func callbackTrampoline(ctx *C.sqlite3_context, argc int, argv **C.sqlite3_value) {
args := (*[(math.MaxInt32 - 1) / unsafe.Sizeof((*C.sqlite3_value)(nil))]*C.sqlite3_value)(unsafe.Pointer(argv))[:argc:argc]
- fi := (*functionInfo)(unsafe.Pointer(C.sqlite3_user_data(ctx)))
+ fi := lookupHandle(uintptr(C.sqlite3_user_data(ctx))).(*functionInfo)
fi.Call(ctx, args)
}
//export stepTrampoline
func stepTrampoline(ctx *C.sqlite3_context, argc int, argv **C.sqlite3_value) {
args := (*[(math.MaxInt32 - 1) / unsafe.Sizeof((*C.sqlite3_value)(nil))]*C.sqlite3_value)(unsafe.Pointer(argv))[:argc:argc]
- ai := (*aggInfo)(unsafe.Pointer(C.sqlite3_user_data(ctx)))
+ ai := lookupHandle(uintptr(C.sqlite3_user_data(ctx))).(*aggInfo)
ai.Step(ctx, args)
}
//export doneTrampoline
func doneTrampoline(ctx *C.sqlite3_context) {
- ai := (*aggInfo)(unsafe.Pointer(C.sqlite3_user_data(ctx)))
+ handle := uintptr(C.sqlite3_user_data(ctx))
+ ai := lookupHandle(handle).(*aggInfo)
ai.Done(ctx)
}
+// Use handles to avoid passing Go pointers to C.
+
+type handleVal struct {
+ db *SQLiteConn
+ val interface{}
+}
+
+var handleLock sync.Mutex
+var handleVals = make(map[uintptr]handleVal)
+var handleIndex uintptr = 100
+
+func newHandle(db *SQLiteConn, v interface{}) uintptr {
+ handleLock.Lock()
+ defer handleLock.Unlock()
+ i := handleIndex
+ handleIndex++
+ handleVals[i] = handleVal{db, v}
+ return i
+}
+
+func lookupHandle(handle uintptr) interface{} {
+ handleLock.Lock()
+ defer handleLock.Unlock()
+ r, ok := handleVals[handle]
+ if !ok {
+ if handle >= 100 && handle < handleIndex {
+ panic("deleted handle")
+ } else {
+ panic("invalid handle")
+ }
+ }
+ return r.val
+}
+
+func deleteHandles(db *SQLiteConn) {
+ handleLock.Lock()
+ defer handleLock.Unlock()
+ for handle, val := range handleVals {
+ if val.db == db {
+ delete(handleVals, handle)
+ }
+ }
+}
+
// This is only here so that tests can refer to it.
type callbackArgRaw C.sqlite3_value