From d111a40ce866dce91bedfb9d8c5d6602b79df9eb Mon Sep 17 00:00:00 2001
From: Veloman Yunkan <veloman.yunkan@gmail.com>
Date: Sat, 23 May 2020 20:35:22 +0400
Subject: [PATCH] Response::m_byteRange

---
 src/server/byte_range.h |  1 +
 src/server/response.cpp | 26 ++++++++++++--------------
 src/server/response.h   |  6 ++----
 3 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/src/server/byte_range.h b/src/server/byte_range.h
index 4579133d3..eb61dde45 100644
--- a/src/server/byte_range.h
+++ b/src/server/byte_range.h
@@ -31,6 +31,7 @@ class ByteRange
 
     int64_t first() const { return first_; }
     int64_t last() const { return last_; }
+    int64_t length() const { return last_ + 1 - first_; }
 
   private: // data
     int64_t first_;
diff --git a/src/server/response.cpp b/src/server/response.cpp
index 23da5c12c..011e8a902 100644
--- a/src/server/response.cpp
+++ b/src/server/response.cpp
@@ -39,12 +39,13 @@ bool is_compressible_mime_type(const std::string& mimeType)
       || mimeType.find("application/json") != string::npos;
 }
 
-int get_range_len(const kiwix::Entry& entry, ByteRange range)
+ByteRange resolve_byte_range(const kiwix::Entry& entry, ByteRange range)
 {
   const int64_t entrySize = entry.getSize();
-  return range.last() == -1
-       ? entrySize - range.first()
-       : std::min(range.last() + 1, entrySize) - range.first();
+  const int64_t resolved_last = range.last() < 0
+                              ? entrySize - 1
+                              : std::min(entrySize-1, range.last());
+  return ByteRange(range.first(), resolved_last);
 }
 
 } // unnamed namespace
@@ -59,9 +60,7 @@ Response::Response(const std::string& root, bool verbose, bool withTaskbar, bool
     m_withLibraryButton(withLibraryButton),
     m_blockExternalLinks(blockExternalLinks),
     m_addTaskbar(false),
-    m_bookName(""),
-    m_startRange(0),
-    m_lenRange(0)
+    m_bookName("")
 {
 }
 
@@ -241,23 +240,24 @@ Response::create_redirection_mhd_response() const
 MHD_Response*
 Response::create_entry_mhd_response() const
 {
-  MHD_Response* response = MHD_create_response_from_callback(m_lenRange,
+  const auto content_length = m_byteRange.length();
+  MHD_Response* response = MHD_create_response_from_callback(content_length,
                                                16384,
                                                callback_reader_from_entry,
-                                               new RunningResponse(m_entry, m_startRange),
+                                               new RunningResponse(m_entry, m_byteRange.first()),
                                                callback_free_response);
   MHD_add_response_header(response,
     MHD_HTTP_HEADER_CONTENT_TYPE, m_mimeType.c_str());
   MHD_add_response_header(response, MHD_HTTP_HEADER_ACCEPT_RANGES, "bytes");
   std::ostringstream oss;
-  oss << "bytes " << m_startRange << "-" << m_startRange + m_lenRange - 1
+  oss << "bytes " << m_byteRange.first() << "-" << m_byteRange.last()
       << "/" << m_entry.getSize();
 
   MHD_add_response_header(response,
     MHD_HTTP_HEADER_CONTENT_RANGE, oss.str().c_str());
 
   MHD_add_response_header(response,
-    MHD_HTTP_HEADER_CONTENT_LENGTH, kiwix::to_string(m_lenRange).c_str());
+    MHD_HTTP_HEADER_CONTENT_LENGTH, kiwix::to_string(content_length).c_str());
   return response;
 }
 
@@ -329,9 +329,7 @@ void Response::set_entry(const Entry& entry, const RequestContext& request) {
     set_content(content);
     set_compress(true);
   } else {
-    const int range_len = get_range_len(entry, request.get_range());
-    set_range_first(request.get_range().first());
-    set_range_len(range_len);
+    m_byteRange = resolve_byte_range(entry, request.get_range());
   }
 }
 
diff --git a/src/server/response.h b/src/server/response.h
index bd15f9543..9fba5a191 100644
--- a/src/server/response.h
+++ b/src/server/response.h
@@ -24,6 +24,7 @@
 #include <string>
 
 #include <mustache.hpp>
+#include "byte_range.h"
 #include "entry.h"
 #include "etag.h"
 
@@ -61,8 +62,6 @@ class Response {
     void set_etag(const ETag& etag) { m_etag = etag; }
     void set_compress(bool compress) { m_compress = compress; }
     void set_taskbar(const std::string& bookName, const std::string& bookTitle);
-    void set_range_first(uint64_t start) { m_startRange = start; }
-    void set_range_len(uint64_t len) { m_lenRange = len; }
 
     int getReturnCode() const { return m_returnCode; }
     std::string get_mimeType() const { return m_mimeType; }
@@ -93,8 +92,7 @@ class Response {
     bool m_addTaskbar;
     std::string m_bookName;
     std::string m_bookTitle;
-    uint64_t m_startRange;
-    uint64_t m_lenRange;
+    ByteRange m_byteRange;
     ETag m_etag;
 };