Add function to read whole of a (maybe active) logfile into memory

renderdoc/os/os_specific.h

@@ -290,6 +290,10 @@ bool logfile_open(const char *filename);
 void logfile_append(const char *msg, size_t length);
 void logfile_close(const char *filename);
 
+// read the whole logfile into memory. This may race with processes writing, but it will read the
+// whole of the file at some point. Useful since normal file reading may fail on the shared logfile
+std::string logfile_readall(const char *filename);
+
 // utility functions
 inline bool dump(const char *filename, const void *buffer, size_t size)
 {

renderdoc/os/posix/posix_stringio.cpp

@@ -484,6 +484,28 @@ void ReleaseFDAfterFork()
     close(logfileFD);
 }
 
+std::string logfile_readall(const char *filename)
+{
+  FILE *f = FileIO::fopen(filename, "r");
+
+  std::string ret;
+
+  if(f == NULL)
+    return ret;
+
+  FileIO::fseek64(f, 0, SEEK_END);
+  uint64_t size = FileIO::ftell64(f);
+  FileIO::fseek64(f, 0, SEEK_SET);
+
+  ret.resize((size_t)size);
+
+  FileIO::fread(&ret[0], 1, ret.size(), f);
+
+  FileIO::fclose(f);
+
+  return ret;
+}
+
 bool logfile_open(const char *filename)
 {
   logfileFD = open(filename, O_APPEND | O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);

renderdoc/os/win32/win32_stringio.cpp

@@ -636,6 +636,30 @@ bool logfile_open(const char *filename)
   return logHandle != NULL;
 }
 
+std::string logfile_readall(const char *filename)
+{
+  wstring wfn = StringFormat::UTF82Wide(string(filename));
+  HANDLE h = CreateFileW(wfn.c_str(), FILE_READ_DATA, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
+                         OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
+
+  std::string ret;
+
+  if(h != NULL)
+  {
+    DWORD len = GetFileSize(h, NULL);
+
+    ret.resize(len);
+
+    DWORD dummy = len;
+
+    ReadFile(h, &ret[0], len, &dummy, NULL);
+
+    CloseHandle(h);
+  }
+
+  return ret;
+}
+
 void logfile_append(const char *msg, size_t length)
 {
   if(logHandle)