perf(util): introduce GetGJSONBytesNoCopy for efficient JSON parsing without data duplication

- Added `GetGJSONBytesNoCopy` in `internal/util` for safe, no-copy JSON parse operations leveraging `unsafe`.
- Replaced `gjson.GetBytes` with the new helper in key payload processing paths (`kimi_executor`, `vertex_payload_helpers`, etc.) to improve performance.
- Added unit tests for behavior validation, including edge cases with empty input.

internal/runtime/executor/helps/payload_helpers.go

@@ -832,7 +832,7 @@ func setPayloadValueIfDifferent(payload []byte, path string, value any) []byte {
 		if expected.Raw == "" {
 			return payload
 		}
-		if current.Raw == expected.Raw {
+		if len(current.Indexes) == 0 && current.Raw == expected.Raw {
 			return payload
 		}
 		updated, errSet := sjson.SetRawBytes(payload, path, []byte(expected.Raw))

internal/runtime/executor/helps/payload_mutations.go

@@ -36,7 +36,7 @@ func SetBoolIfDifferent(payload []byte, path string, value bool) []byte {
 // SetRawIfDifferent updates path only when the existing raw JSON is identical.
 func SetRawIfDifferent(payload []byte, path string, value []byte) []byte {
 	current := gjson.GetBytes(payload, path)
-	if current.Exists() && current.Raw == string(value) {
+	if current.Exists() && len(current.Indexes) == 0 && current.Raw == string(value) {
 		return payload
 	}
 	updated, errSet := sjson.SetRawBytes(payload, path, value)

internal/runtime/executor/helps/payload_mutations_test.go

@@ -92,6 +92,38 @@ func TestApplyPayloadConfigReusesCanonicalOverrides(t *testing.T) {
 	}
 }
 
+func TestApplyPayloadConfigProjectionOverrideWritesEveryMatch(t *testing.T) {
+	cfg := &config.Config{Payload: config.PayloadConfig{
+		Override: []config.PayloadRule{{
+			Models: []config.PayloadModelRule{{Name: "gpt-test", Protocol: "openai"}},
+			Params: map[string]any{"items.#.value": []any{1, 2}},
+		}},
+	}}
+	input := []byte(`{"items":[{"value":1},{"value":2}]}`)
+	output := ApplyPayloadConfigWithRoot(cfg, "gpt-test", "openai", "", input, nil, "", "")
+	for _, path := range []string{"items.0.value", "items.1.value"} {
+		if got := gjson.GetBytes(output, path).Raw; got != `[1,2]` {
+			t.Fatalf("%s = %s, want [1,2]", path, got)
+		}
+	}
+}
+
+func TestApplyPayloadConfigProjectionOverrideRawWritesEveryMatch(t *testing.T) {
+	cfg := &config.Config{Payload: config.PayloadConfig{
+		OverrideRaw: []config.PayloadRule{{
+			Models: []config.PayloadModelRule{{Name: "gpt-test", Protocol: "openai"}},
+			Params: map[string]any{"items.#.value": `[1,2]`},
+		}},
+	}}
+	input := []byte(`{"items":[{"value":1},{"value":2}]}`)
+	output := ApplyPayloadConfigWithRoot(cfg, "gpt-test", "openai", "", input, nil, "", "")
+	for _, path := range []string{"items.0.value", "items.1.value"} {
+		if got := gjson.GetBytes(output, path).Raw; got != `[1,2]` {
+			t.Fatalf("%s = %s, want [1,2]", path, got)
+		}
+	}
+}
+
 func TestApplyPayloadConfigNormalizesByteSliceOverride(t *testing.T) {
 	cfg := &config.Config{Payload: config.PayloadConfig{
 		Override: []config.PayloadRule{{

internal/runtime/executor/helps/vertex_payload_helpers.go

@@ -3,6 +3,7 @@ package helps
 import (
 	"strings"
 
+	"github.com/router-for-me/CLIProxyAPI/v7/internal/util"
 	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"
 )
@@ -14,7 +15,7 @@ func StripVertexOpenAIResponsesToolCallIDs(payload []byte, sourceFormat string)
 		return payload
 	}
 
-	contents := gjson.GetBytes(payload, "contents")
+	contents := util.GetGJSONBytesNoCopy(payload, "contents")
 	if !contents.IsArray() || !vertexContentsHaveToolCallIDs(contents) {
 		return payload
 	}

internal/runtime/executor/kimi_executor.go

@@ -344,7 +344,7 @@ func normalizeKimiToolMessageLinks(body []byte) ([]byte, error) {
 		return body, nil
 	}
 
-	messages := gjson.GetBytes(body, "messages")
+	messages := util.GetGJSONBytesNoCopy(body, "messages")
 	if !messages.Exists() || !messages.IsArray() {
 		return body, nil
 	}

internal/signature/gemini_sanitize.go

@@ -3,6 +3,7 @@ package signature
 import (
 	"strings"
 
+	"github.com/router-for-me/CLIProxyAPI/v7/internal/util"
 	log "github.com/sirupsen/logrus"
 	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"
@@ -32,7 +33,7 @@ func SanitizeGeminiRequestThoughtSignatures(payload []byte, contentsPath string)
 		contentsPath = "contents"
 	}
 
-	contents := gjson.GetBytes(payload, contentsPath)
+	contents := util.GetGJSONBytesNoCopy(payload, contentsPath)
 	if !contents.IsArray() || !geminiContentsThoughtSignaturesNeedSanitize(contents) {
 		return payload
 	}

internal/util/gjson.go

@@ -0,0 +1,16 @@
+package util
+
+import (
+	"unsafe"
+
+	"github.com/tidwall/gjson"
+)
+
+// GetGJSONBytesNoCopy returns a GJSON result that may reference data directly.
+// Callers must not retain the result or mutate data while using it.
+func GetGJSONBytesNoCopy(data []byte, path string) gjson.Result {
+	if len(data) == 0 {
+		return gjson.Result{}
+	}
+	return gjson.Get(unsafe.String(unsafe.SliceData(data), len(data)), path)
+}

internal/util/gjson_test.go

@@ -0,0 +1,17 @@
+package util
+
+import "testing"
+
+func TestGetGJSONBytesNoCopy(t *testing.T) {
+	input := []byte(`{"request":{"contents":[{"role":"user"}]}}`)
+	contents := GetGJSONBytesNoCopy(input, "request.contents")
+	if !contents.IsArray() || contents.Get("0.role").String() != "user" {
+		t.Fatalf("request.contents = %s, want user content array", contents.Raw)
+	}
+}
+
+func TestGetGJSONBytesNoCopyEmptyInput(t *testing.T) {
+	if result := GetGJSONBytesNoCopy(nil, "contents"); result.Exists() {
+		t.Fatalf("empty input result = %s, want missing", result.Raw)
+	}
+}