PNGLoader: Use MappedFile.

cubiclove · Apr 3, 2019 · c0009e3 · c0009e3
1 parent 3dc3754
commit c0009e3
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Showing 3 changed files with 21 additions and 46 deletions.
diff --git a/AK/MappedFile.cpp b/AK/MappedFile.cpp
@@ -5,25 +5,29 @@
 #include <unistd.h>
 #include <stdio.h>
 
+//#define DEBUG_MAPPED_FILE
+
 namespace AK {
 
 MappedFile::MappedFile(const String& file_name)
  : m_file_name(file_name)
 {
- m_file_length = PAGE_SIZE;
+ m_size = PAGE_SIZE;
  m_fd = open(m_file_name.characters(), O_RDONLY);
 
  if (m_fd != -1) {
  struct stat st;
  fstat(m_fd, &st);
- m_file_length = st.st_size;
- m_map = mmap(nullptr, m_file_length, PROT_READ, MAP_SHARED, m_fd, 0);
+ m_size = st.st_size;
+ m_map = mmap(nullptr, m_size, PROT_READ, MAP_SHARED, m_fd, 0);
 
  if (m_map == MAP_FAILED)
  perror("");
  }
 
- dbgprintf("MappedFile{%s} := { m_fd=%d, m_file_length=%zu, m_map=%p }\n", m_file_name.characters(), m_fd, m_file_length, m_map);
+#ifdef DEBUG_MAPPED_FILE
+ dbgprintf("MappedFile{%s} := { m_fd=%d, m_size=%u, m_map=%p }\n", m_file_name.characters(), m_fd, m_size, m_map);
+#endif
 }
 
 MappedFile::~MappedFile()
@@ -36,21 +40,23 @@ void MappedFile::unmap()
  if (!is_valid())
  return;
  ASSERT(m_fd != -1);
- int rc = munmap(m_map, m_file_length);
+ int rc = munmap(m_map, m_size);
+ ASSERT(rc == 0);
+ rc = close(m_fd);
  ASSERT(rc == 0);
  m_file_name = { };
- m_file_length = 0;
+ m_size = 0;
  m_fd = -1;
  m_map = (void*)-1;
 }
 
 MappedFile::MappedFile(MappedFile&& other)
  : m_file_name(move(other.m_file_name))
- , m_file_length(other.m_file_length)
+ , m_size(other.m_size)
  , m_fd(other.m_fd)
  , m_map(other.m_map)
 {
- other.m_file_length = 0;
+ other.m_size = 0;
  other.m_fd = -1;
  other.m_map = (void*)-1;
 }
@@ -61,7 +67,7 @@ MappedFile& MappedFile::operator=(MappedFile&& other)
  return *this;
  unmap();
  swap(m_file_name, other.m_file_name);
- swap(m_file_length, other.m_file_length);
+ swap(m_size, other.m_size);
  swap(m_fd, other.m_fd);
  swap(m_map, other.m_map);
  return *this;

diff --git a/AK/MappedFile.h b/AK/MappedFile.h
@@ -18,11 +18,11 @@ class MappedFile {
 
  void* pointer() { return m_map; }
  const void* pointer() const { return m_map; }
- size_t file_length() const { return m_file_length; }
+ size_t size() const { return m_size; }
 
 private:
  String m_file_name;
- size_t m_file_length { 0 };
+ size_t m_size { 0 };
  int m_fd { -1 };
  void* m_map { (void*)-1 };
 };

diff --git a/SharedGraphics/PNGLoader.cpp b/SharedGraphics/PNGLoader.cpp
@@ -1,5 +1,6 @@
 #include <SharedGraphics/PNGLoader.h>
 #include <AK/NetworkOrdered.h>
+#include <AK/MappedFile.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
 #include <unistd.h>
@@ -101,42 +102,10 @@ static bool process_chunk(Streamer&, PNGLoadingContext& context);
 
 RetainPtr<GraphicsBitmap> load_png(const String& path)
 {
- int fd = open(path.characters(), O_RDONLY);
- if (fd < 0) {
- perror("open");
+ MappedFile mapped_file(path);
+ if (!mapped_file.is_valid())
  return nullptr;
- }
-
- struct stat st;
- if (fstat(fd, &st) < 0) {
- perror("fstat");
- if (close(fd) < 0)
- perror("close");
- return nullptr;
- }
-
- if (st.st_size < 8) {
- if (close(fd) < 0)
- perror("close");
- return nullptr;
- }
-
- auto* mapped_file = (byte*)mmap(nullptr, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
- if (mapped_file == MAP_FAILED) {
- if (close(fd) < 0)
- perror("close");
- return nullptr;
- }
-
- auto bitmap = load_png_impl(mapped_file, st.st_size);
-
- if (munmap(mapped_file, st.st_size) < 0)
- perror("munmap");
-
- if (close(fd) < 0)
- perror("close");
-
- return bitmap;
+ return load_png_impl((const byte*)mapped_file.pointer(), mapped_file.size());
 }
 
 [[gnu::always_inline]] static inline byte paeth_predictor(int a, int b, int c)