Timestamps in log file names

src/log.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 13 matching lines @@
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <stdarg.h>
 
 #include "v8.h"
 
 #include "log.h"
 #include "platform.h"
+#include "string-stream.h"
 
 namespace v8 { namespace internal {
 
 #ifdef ENABLE_LOGGING_AND_PROFILING
 
 //
 // Sliding state window.  Updates counters to keep track of the last
 // window of kBufferSize states.  This is useful to track where we
 // spent our time.
 //
@@ skipping 635 matching lines @@
   if (FLAG_prof) FLAG_log_code = true;
 
   bool open_log_file = FLAG_log || FLAG_log_api || FLAG_log_code
       || FLAG_log_gc || FLAG_log_handles || FLAG_log_suspect
       || FLAG_log_regexp;
 
   // If we're logging anything, we need to open the log file.
   if (open_log_file) {
     if (strcmp(FLAG_logfile, "-") == 0) {
       logfile_ = stdout;
+    } else if (strchr(FLAG_logfile, '%') != NULL) {
+      // If there's a '%' in the log file name we have to expand
+      // placeholders.
+      HeapStringAllocator allocator;
+      StringStream stream(&allocator);
+      for (const char* p = FLAG_logfile; *p; p++) {
+        if (*p == '%') {
+          p++;
+          switch (*p) {
+            case '\0':
+              // If there's a % at the end of the string we back up
+              // one character so we can escape the loop properly.
+              p--;
+              break;
+            case 't': {
+              // %t expands to the current time in milliseconds.
+              uint32_t time = static_cast<uint32_t>(OS::TimeCurrentMillis());
+              stream.Add("%u", time);
+              break;
+            }
+            default:
+              // All other %'s expand to themselves.

[Erik Corry, 2008/10/15 08:36:01]

IMHO they should expand to % followed by themselves.

[Christian Plesner Hansen, 2008/10/15 08:46:32]

Sure, I'll change it -- I don't really care.  I did it this way because then %%
expands to %.

+              stream.Put(*p);
+              break;
+          }
+        } else {
+          stream.Put(*p);
+        }
+      }
+      SmartPointer<char> expanded = stream.ToCString();
+      logfile_ = OS::FOpen(*expanded, "w");
     } else {
       logfile_ = OS::FOpen(FLAG_logfile, "w");
     }
     mutex_ = OS::CreateMutex();
   }
 
   current_state_ = new VMState(OTHER);
 
   ticker_ = new Ticker(10);
 
@@ skipping 98 matching lines @@
   if (FLAG_log_state_changes) {
     LOG(StringEvent("Leaving", StateToString(state_)));
     if (previous_) {
       LOG(StringEvent("To", StateToString(previous_->state_)));
     }
   }
 }
 #endif
 
 } }  // namespace v8::internal