refactor: add a tr_loadFile() variant that takes a reusable buffer (#2181)

libtransmission/torrent-ctor.cc

@@ -52,6 +52,8 @@ struct tr_ctor
     std::vector<tr_file_index_t> normal;
     std::vector<tr_file_index_t> high;
 
+    std::vector<char> contents;
+
     explicit tr_ctor(tr_session const* session_in)
         : session{ session_in }
     {
@@ -113,33 +115,29 @@ int tr_ctorSetMetainfoFromMagnetLink(tr_ctor* ctor, char const* magnet_link)
 
 int tr_ctorSetMetainfoFromFile(tr_ctor* ctor, char const* filename)
 {
-    auto len = size_t{};
-    auto* const metainfo = tr_loadFile(filename, &len, nullptr);
-
-    auto err = int{};
-    if (metainfo != nullptr && len != 0)
-    {
-        err = tr_ctorSetMetainfo(ctor, metainfo, len);
-    }
-    else
+    if (!tr_loadFile(ctor->contents, filename, nullptr) || std::empty(ctor->contents))
     {
         clearMetainfo(ctor);
-        err = 1;
+        return EILSEQ;
+    }
+
+    int const err = tr_ctorSetMetainfo(ctor, std::data(ctor->contents), std::size(ctor->contents));
+    if (err)
+    {
+        clearMetainfo(ctor);
+        return err;
     }
 
     setSourceFile(ctor, filename);
 
     /* if no `name' field was set, then set it from the filename */
-    if (ctor->isSet_metainfo)
-    {
     tr_variant* info = nullptr;
 
     if (tr_variantDictFindDict(&ctor->metainfo, TR_KEY_info, &info))
     {
         auto name = std::string_view{};
 
-            if (!tr_variantDictFindStrView(info, TR_KEY_name_utf_8, &name) &&
-                !tr_variantDictFindStrView(info, TR_KEY_name, &name))
+        if (!tr_variantDictFindStrView(info, TR_KEY_name_utf_8, &name) && !tr_variantDictFindStrView(info, TR_KEY_name, &name))
         {
             name = ""sv;
         }
@@ -155,10 +153,8 @@ int tr_ctorSetMetainfoFromFile(tr_ctor* ctor, char const* filename)
             }
         }
     }
-    }
 
-    tr_free(metainfo);
-    return err;
+    return 0;
 }
 
 /***

libtransmission/utils.cc

@@ -336,6 +336,49 @@ uint8_t* tr_loadFile(char const* path, size_t* size, tr_error** error)
     return buf;
 }
 
+bool tr_loadFile(std::vector<char>& setme, char const* path, tr_error** error)
+{
+    char const* const err_fmt = _("Couldn't read \"%1$s\": %2$s");
+
+    /* try to stat the file */
+    auto info = tr_sys_path_info{};
+    tr_error* my_error = nullptr;
+    if (!tr_sys_path_get_info(path, 0, &info, &my_error))
+    {
+        tr_logAddDebug(err_fmt, path, my_error->message);
+        tr_error_propagate(error, &my_error);
+        return false;
+    }
+
+    if (info.type != TR_SYS_PATH_IS_FILE)
+    {
+        tr_logAddError(err_fmt, path, _("Not a regular file"));
+        tr_error_set_literal(error, TR_ERROR_EISDIR, _("Not a regular file"));
+        return false;
+    }
+
+    /* Load the torrent file into our buffer */
+    tr_sys_file_t const fd = tr_sys_file_open(path, TR_SYS_FILE_READ | TR_SYS_FILE_SEQUENTIAL, 0, &my_error);
+    if (fd == TR_BAD_SYS_FILE)
+    {
+        tr_logAddError(err_fmt, path, my_error->message);
+        tr_error_propagate(error, &my_error);
+        return false;
+    }
+
+    setme.resize(info.size);
+    if (!tr_sys_file_read(fd, std::data(setme), info.size, nullptr, &my_error))
+    {
+        tr_logAddError(err_fmt, path, my_error->message);
+        tr_sys_file_close(fd, nullptr);
+        tr_error_propagate(error, &my_error);
+        return false;
+    }
+
+    tr_sys_file_close(fd, nullptr);
+    return true;
+}
+
 char* tr_buildPath(char const* first_element, ...)
 {
 

libtransmission/utils.h

@@ -79,6 +79,8 @@ bool tr_wildmat(char const* text, char const* pattern) TR_GNUC_NONNULL(1, 2);
  */
 uint8_t* tr_loadFile(char const* filename, size_t* size, struct tr_error** error) TR_GNUC_MALLOC TR_GNUC_NONNULL(1);
 
+bool tr_loadFile(std::vector<char>& setme, char const* filename, tr_error** error = nullptr);
+
 /** @brief build a filename from a series of elements using the
            platform's correct directory separator. */
 char* tr_buildPath(char const* first_element, ...) TR_GNUC_NULL_TERMINATED TR_GNUC_MALLOC;