files: always initialize inspect_window and min_inspect_depth

This is to make sure the files buffers are properly managed even
when there are no rules or when there are no file.data rules.

Bug: #5703.

src/detect-file-data.c

@@ -163,10 +163,6 @@ void DetectFiledataRegister(void)
     g_file_data_buffer_id = DetectBufferTypeGetByName("file_data");
 }
 
-#define FILEDATA_CONTENT_LIMIT 100000
-#define FILEDATA_CONTENT_INSPECT_MIN_SIZE 32768
-#define FILEDATA_CONTENT_INSPECT_WINDOW 4096
-
 static void SetupDetectEngineConfig(DetectEngineCtx *de_ctx) {
     if (de_ctx->filedata_config_initialized)
         return;

src/util-file.c

@@ -955,6 +955,9 @@ static File *FileOpenFile(FileContainer *ffc, const StreamingBufferConfig *sbcfg
 
     FileContainerAdd(ffc, ff);
 
+    /* set default window and min inspection size */
+    FileSetInspectSizes(ff, FILEDATA_CONTENT_INSPECT_WINDOW, FILEDATA_CONTENT_INSPECT_MIN_SIZE);
+
     ff->size += data_len;
     if (data != NULL) {
         if (AppendData(ff, data, data_len) != 0) {

src/util-file.h

@@ -61,6 +61,10 @@ typedef struct SCMd5 SCMd5;
 // to be used instead of PATH_MAX which depends on the OS
 #define SC_FILENAME_MAX 4096
 
+#define FILEDATA_CONTENT_LIMIT            100000
+#define FILEDATA_CONTENT_INSPECT_MIN_SIZE 32768
+#define FILEDATA_CONTENT_INSPECT_WINDOW   4096
+
 typedef enum FileState_ {
     FILE_STATE_NONE = 0,    /**< no state */
     FILE_STATE_OPENED,      /**< flow file is opened */