Common: Make recursive FileUtil functions take a maximum recursion

Fixes #1115.

Also improves the performances of DiskArchive’s directory
implementation a lot, simply by not going through the entire tree
instead of just listing the first level files.

Thanks to JayRoxFox for rebasing this on current master!

2 files changed, 36 insertions, 24 deletions

diff --git a/src/common/file_util.cpp b/src/common/file_util.cpp
index 6e2867658..17af7c385 100644
--- a/src/common/file_util.cpp
+++ b/src/common/file_util.cpp
@@ -434,7 +434,7 @@ bool CreateEmptyFile(const std::string &filename)
 }
 
 
-bool ForeachDirectoryEntry(unsigned* num_entries_out, const std::string &directory, DirectoryEntryCallable callback)
+bool ForeachDirectoryEntry(unsigned* num_entries_out, const std::string &directory, DirectoryEntryCallable callback, unsigned int recursion)
 {
     LOG_TRACE(Common_Filesystem, "directory %s", directory.c_str());
 
@@ -472,7 +472,7 @@ bool ForeachDirectoryEntry(unsigned* num_entries_out, const std::string &directo
             continue;
 
         unsigned ret_entries = 0;
-        if (!callback(&ret_entries, directory, virtual_name)) {
+        if (!callback(&ret_entries, directory, virtual_name, recursion)) {
             callback_error = true;
             break;
         }
@@ -486,30 +486,34 @@ bool ForeachDirectoryEntry(unsigned* num_entries_out, const std::string &directo
     closedir(dirp);
 #endif
 
-    if (!callback_error) {
-        // num_entries_out is allowed to be specified nullptr, in which case we shouldn't try to set it
-        if (num_entries_out != nullptr)
-            *num_entries_out = found_entries;
-        return true;
-    } else {
+    if (callback_error)
         return false;
-    }
+
+    // num_entries_out is allowed to be specified nullptr, in which case we shouldn't try to set it
+    if (num_entries_out != nullptr)
+        *num_entries_out = found_entries;
+    return true;
 }
 
-unsigned ScanDirectoryTree(const std::string &directory, FSTEntry& parent_entry)
+unsigned ScanDirectoryTree(const std::string &directory, FSTEntry& parent_entry, unsigned int recursion)
 {
     const auto callback = [&parent_entry](unsigned* num_entries_out,
                                           const std::string& directory,
-                                          const std::string& virtual_name) -> bool {
+                                          const std::string& virtual_name,
+                                          unsigned int recursion) -> bool {
         FSTEntry entry;
         entry.virtualName = virtual_name;
         entry.physicalName = directory + DIR_SEP + virtual_name;
 
         if (IsDirectory(entry.physicalName)) {
             entry.isDirectory = true;
-            // is a directory, lets go inside
-            entry.size = ScanDirectoryTree(entry.physicalName, entry);
-            *num_entries_out += (int)entry.size;
+            // is a directory, lets go inside if we didn't recurse to often
+            if (recursion > 0) {
+                entry.size = ScanDirectoryTree(entry.physicalName, entry, recursion - 1);
+                *num_entries_out += (int)entry.size;
+            } else {
+                entry.size = 0;
+            }
         } else { // is a file
             entry.isDirectory = false;
             entry.size = GetSize(entry.physicalName);
@@ -522,23 +526,27 @@ unsigned ScanDirectoryTree(const std::string &directory, FSTEntry& parent_entry)
     };
 
     unsigned num_entries;
-    return ForeachDirectoryEntry(&num_entries, directory, callback) ? num_entries : 0;
+    return ForeachDirectoryEntry(&num_entries, directory, callback, recursion) ? num_entries : 0;
 }
 
 
-bool DeleteDirRecursively(const std::string &directory)
+bool DeleteDirRecursively(const std::string &directory, unsigned int recursion)
 {
     const static auto callback = [](unsigned* num_entries_out,
                                     const std::string& directory,
-                                    const std::string& virtual_name) -> bool {
+                                    const std::string& virtual_name,
+                                    unsigned int recursion) -> bool {
         std::string new_path = directory + DIR_SEP_CHR + virtual_name;
-        if (IsDirectory(new_path))
-            return DeleteDirRecursively(new_path);
 
+        if (IsDirectory(new_path)) {
+            if (recursion == 0)
+                return false;
+            return DeleteDirRecursively(new_path, recursion - 1);
+        }
         return Delete(new_path);
     };
 
-    if (!ForeachDirectoryEntry(nullptr, directory, callback))
+    if (!ForeachDirectoryEntry(nullptr, directory, callback, recursion))
         return false;
 
     // Delete the outermost directory
diff --git a/src/common/file_util.h b/src/common/file_util.h
index c6a8694ce..32ae2dc57 100644
--- a/src/common/file_util.h
+++ b/src/common/file_util.h
@@ -105,11 +105,13 @@ bool CreateEmptyFile(const std::string &filename);
  * @param num_entries_out to be assigned by the callable with the number of iterated directory entries, never null
  * @param directory the path to the enclosing directory
  * @param virtual_name the entry name, without any preceding directory info
+ * @param recursion Number of children directory to read before giving up
  * @return whether handling the entry succeeded
  */
 using DirectoryEntryCallable = std::function<bool(unsigned* num_entries_out,
                                                  const std::string& directory,
-                                                 const std::string& virtual_name)>;
+                                                 const std::string& virtual_name,
+                                                 unsigned int recursion)>;
 
 /**
  * Scans a directory, calling the callback for each file/directory contained within.
@@ -117,20 +119,22 @@ using DirectoryEntryCallable = std::function<bool(unsigned* num_entries_out,
  * @param num_entries_out assigned by the function with the number of iterated directory entries, can be null
  * @param directory the directory to scan
  * @param callback The callback which will be called for each entry
+ * @param recursion Number of children directories to read before giving up
  * @return whether scanning the directory succeeded
  */
-bool ForeachDirectoryEntry(unsigned* num_entries_out, const std::string &directory, DirectoryEntryCallable callback);
+bool ForeachDirectoryEntry(unsigned* num_entries_out, const std::string &directory, DirectoryEntryCallable callback, unsigned int recursion = 0);
 
 /**
  * Scans the directory tree, storing the results.
  * @param directory the parent directory to start scanning from
  * @param parent_entry FSTEntry where the filesystem tree results will be stored.
+ * @param recursion Number of children directories to read before giving up.
  * @return the total number of files/directories found
  */
-unsigned ScanDirectoryTree(const std::string &directory, FSTEntry& parent_entry);
+unsigned ScanDirectoryTree(const std::string &directory, FSTEntry& parent_entry, unsigned int recursion = 0);
 
 // deletes the given directory and anything under it. Returns true on success.
-bool DeleteDirRecursively(const std::string &directory);
+bool DeleteDirRecursively(const std::string &directory, unsigned int recursion = 256);
 
 // Returns the current directory
 std::string GetCurrentDir();