1 files changed, 214 insertions, 0 deletions
diff --git a/vendor/github.com/bytedance/sonic/internal/resolver/resolver.go b/vendor/github.com/bytedance/sonic/internal/resolver/resolver.go
new file mode 100644
index 000000000..796d5d823
--- /dev/null
+++ b/vendor/github.com/bytedance/sonic/internal/resolver/resolver.go
@@ -0,0 +1,214 @@
+/*
+ * Copyright 2021 ByteDance Inc.
+ *
+ * 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.
+ */
+
+package resolver
+
+import (
+    `fmt`
+    `reflect`
+    `strings`
+    `sync`
+)
+
+type FieldOpts int
+type OffsetType int
+
+const (
+    F_omitempty FieldOpts = 1 << iota
+    F_stringize
+)
+
+const (
+    F_offset OffsetType = iota
+    F_deref
+)
+
+type Offset struct {
+    Size uintptr
+    Kind OffsetType
+    Type reflect.Type
+}
+
+type FieldMeta struct {
+    Name string
+    Path []Offset
+    Opts FieldOpts
+    Type reflect.Type
+}
+
+func (self *FieldMeta) String() string {
+    var path []string
+    var opts []string
+
+    /* dump the field path */
+    for _, off := range self.Path {
+        if off.Kind == F_offset {
+            path = append(path, fmt.Sprintf("%d", off.Size))
+        } else {
+            path = append(path, fmt.Sprintf("%d.(*%s)", off.Size, off.Type))
+        }
+    }
+
+    /* check for "string" */
+    if (self.Opts & F_stringize) != 0 {
+        opts = append(opts, "string")
+    }
+
+    /* check for "omitempty" */
+    if (self.Opts & F_omitempty) != 0 {
+        opts = append(opts, "omitempty")
+    }
+
+    /* format the field */
+    return fmt.Sprintf(
+        "{Field \"%s\" @ %s, opts=%s, type=%s}",
+        self.Name,
+        strings.Join(path, "."),
+        strings.Join(opts, ","),
+        self.Type,
+    )
+}
+
+func (self *FieldMeta) optimize() {
+    var n int
+    var v uintptr
+
+    /* merge adjacent offsets */
+    for _, o := range self.Path {
+        if v += o.Size; o.Kind == F_deref {
+            self.Path[n].Size    = v
+            self.Path[n].Type, v = o.Type, 0
+            self.Path[n].Kind, n = F_deref, n + 1
+        }
+    }
+
+    /* last offset value */
+    if v != 0 {
+        self.Path[n].Size = v
+        self.Path[n].Type = nil
+        self.Path[n].Kind = F_offset
+        n++
+    }
+
+    /* must be at least 1 offset */
+    if n != 0 {
+        self.Path = self.Path[:n]
+    } else {
+        self.Path = []Offset{{Kind: F_offset}}
+    }
+}
+
+func resolveFields(vt reflect.Type) []FieldMeta {
+    tfv := typeFields(vt)
+    ret := []FieldMeta(nil)
+
+    /* convert each field */
+    for _, fv := range tfv.list {
+        item := vt
+        path := []Offset(nil)
+        opts := FieldOpts(0)
+
+        /* check for "string" */
+        if fv.quoted {
+            opts |= F_stringize
+        }
+
+        /* check for "omitempty" */
+        if fv.omitEmpty {
+            opts |= F_omitempty
+        }
+
+        /* dump the field path */
+        for _, i := range fv.index {
+            kind := F_offset
+            fval := item.Field(i)
+            item  = fval.Type
+
+            /* deref the pointer if needed */
+            if item.Kind() == reflect.Ptr {
+                kind = F_deref
+                item = item.Elem()
+            }
+
+            /* add to path */
+            path = append(path, Offset {
+                Kind: kind,
+                Type: item,
+                Size: fval.Offset,
+            })
+        }
+
+        /* get the index to the last offset */
+        fvt := fv.typ
+        idx := len(path) - 1
+
+        /* do not dereference into fields */
+        if path[idx].Kind == F_deref {
+            fvt = reflect.PtrTo(fvt)
+            path[idx].Kind = F_offset
+        }
+
+        /* add to result */
+        ret = append(ret, FieldMeta {
+            Type: fvt,
+            Opts: opts,
+            Path: path,
+            Name: fv.name,
+        })
+    }
+
+    /* optimize the offsets */
+    for i := range ret {
+        ret[i].optimize()
+    }
+
+    /* all done */
+    return ret
+}
+
+var (
+    fieldLock  = sync.RWMutex{}
+    fieldCache = map[reflect.Type][]FieldMeta{}
+)
+
+func ResolveStruct(vt reflect.Type) []FieldMeta {
+    var ok bool
+    var fm []FieldMeta
+
+    /* attempt to read from cache */
+    fieldLock.RLock()
+    fm, ok = fieldCache[vt]
+    fieldLock.RUnlock()
+
+    /* check if it was cached */
+    if ok {
+        return fm
+    }
+
+    /* otherwise use write-lock */
+    fieldLock.Lock()
+    defer fieldLock.Unlock()
+
+    /* double check */
+    if fm, ok = fieldCache[vt]; ok {
+        return fm
+    }
+
+    /* resolve the field */
+    fm = resolveFields(vt)
+    fieldCache[vt] = fm
+    return fm
+}