Change the allocation of the stdout and stderr collected by Process.runSync

runtime/bin/process_linux.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_LINUX)
 
 #include "bin/process.h"
 
 #include <errno.h>  // NOLINT
 #include <fcntl.h>  // NOLINT
 #include <poll.h>  // NOLINT
 #include <signal.h>  // NOLINT
 #include <stdio.h>  // NOLINT
 #include <stdlib.h>  // NOLINT
 #include <string.h>  // NOLINT
 #include <sys/wait.h>  // NOLINT
 #include <unistd.h>  // NOLINT
 
 #include "bin/fdutils.h"
 #include "bin/log.h"
 #include "bin/thread.h"
 
+
 extern char **environ;
 
 
 namespace dart {
 namespace bin {
 
 // ProcessInfo is used to map a process id to the file descriptor for
 // the pipe used to communicate the exit code of the process to Dart.
 // ProcessInfo objects are kept in the static singly-linked
 // ProcessInfoList.
@@ skipping 527 matching lines @@
   TEMP_FAILURE_RETRY(close(write_out[0]));
   FDUtils::SetNonBlocking(read_err[0]);
   *err = read_err[0];
   TEMP_FAILURE_RETRY(close(read_err[1]));
 
   *id = pid;
   return 0;
 }
 
 
-static bool ReadProcessBuffer(uint8_t** buffer,
-                              intptr_t* buffer_length,
-                              intptr_t available,
-                              int fd) {
-  uint8_t* tmp = new uint8_t[*buffer_length + available];
-  if (tmp == NULL) FATAL("Allocation failed");
-  memmove(tmp, *buffer, *buffer_length);
-  delete[] *buffer;
-  *buffer = tmp;
-  intptr_t bytes = TEMP_FAILURE_RETRY(read(
-      fd,
-      reinterpret_cast<void*>(*buffer + *buffer_length),
-      available));
-  if (bytes < 0) return false;
-  *buffer_length += bytes;
-  return true;
-}
+class BufferList: public BufferListBase {
+ public:
+  bool Read(int fd, intptr_t available) {
+    // Read all available bytes.
+    while (available > 0) {
+      if (free_size_ == 0) Allocate();
+      ASSERT(free_size_ > 0);
+      ASSERT(free_size_ <= kBufferSize);
+      intptr_t block_size = dart::Utils::Minimum(free_size_, available);
+      intptr_t bytes = TEMP_FAILURE_RETRY(read(
+          fd,
+          reinterpret_cast<void*>(tail_->data_ + (kBufferSize - free_size_)),
+          block_size));
+      if (bytes < 0) return false;
+      data_size_ += bytes;
+      free_size_ -= bytes;
+      available -= bytes;
+    }
+    return true;
+  }
+};
 
 
 static bool CloseProcessBuffers(struct pollfd fds[3]) {
   int e = errno;
   VOID_TEMP_FAILURE_RETRY(close(fds[0].fd));
   VOID_TEMP_FAILURE_RETRY(close(fds[1].fd));
   VOID_TEMP_FAILURE_RETRY(close(fds[2].fd));
   errno = e;
   return false;
 }
 
 
 bool Process::Wait(intptr_t pid,
                    intptr_t in,
                    intptr_t out,
                    intptr_t err,
                    intptr_t exit_event,
                    ProcessResult* result) {
   // Close input to the process right away.
   VOID_TEMP_FAILURE_RETRY(close(in));
 
-  uint8_t* out_data = NULL;
-  intptr_t out_data_length = 0;
-  uint8_t* err_data = NULL;
-  intptr_t err_data_length = 0;
+  // There is no return from this function using Dart_PropagateError
+  // as memory used by the buffer lists is freed through their
+  // destructors.
+  BufferList out_data;
+  BufferList err_data;
   union {
     uint8_t bytes[8];
     int32_t ints[2];
   } exit_code_data;
 
   struct pollfd fds[3];
   fds[0].fd = out;
   fds[1].fd = err;
   fds[2].fd = exit_event;
 
   for (int i = 0; i < 3; i++) {
     fds[i].events = POLLIN;
   }
 
   int alive = 3;
   while (alive > 0) {
     // Blocking call waiting for events from the child process.
     if (TEMP_FAILURE_RETRY(poll(fds, alive, -1)) <= 0) {
       return CloseProcessBuffers(fds);
     }
+
+    // Process incoming data.
     for (int i = 0; i < alive; i++) {
       if (fds[i].revents & POLLIN) {
         intptr_t avail = FDUtils::AvailableBytes(fds[i].fd);
         if (fds[i].fd == out) {
-          if (!ReadProcessBuffer(&out_data, &out_data_length, avail, out)) {
+          if (!out_data.Read(out, avail)) {
             return CloseProcessBuffers(fds);
           }
         } else if (fds[i].fd == err) {
-          if (!ReadProcessBuffer(&err_data, &err_data_length, avail, err)) {
+          if (!err_data.Read(err, avail)) {
             return CloseProcessBuffers(fds);
           }
         } else if (fds[i].fd == exit_event) {
           if (avail == 8) {
-            intptr_t b = TEMP_FAILURE_RETRY(read(fds[i].fd,
+            intptr_t b = TEMP_FAILURE_RETRY(read(exit_event,
                                                  exit_code_data.bytes, 8));
             if (b != 8) {
               return CloseProcessBuffers(fds);
             }
           }
         } else {
           UNREACHABLE();
         }
-        continue;
       }
+    }
 
+    // Process closed.
+    for (int i = 0; i < alive; i++) {
       if (fds[i].revents & POLLHUP) {
         VOID_TEMP_FAILURE_RETRY(close(fds[i].fd));
         alive--;
         if (i < alive) {
           fds[i] = fds[alive];
         }
       }
     }
   }
 
   // All handles closed and all data read.
-  result->SetStdoutData(out_data, out_data_length);
-  result->SetStderrData(err_data, err_data_length);
+  result->set_stdout_data(out_data.GetData());
+  result->set_stderr_data(err_data.GetData());
 
   // Calculate the exit code.
   intptr_t exit_code = exit_code_data.ints[0];
   intptr_t negative = exit_code_data.ints[1];
   if (negative) exit_code = -exit_code;
   result->set_exit_code(exit_code);
 
   return true;
 }
 
 
 bool Process::Kill(intptr_t id, int signal) {
   return (TEMP_FAILURE_RETRY(kill(id, signal)) != -1);
 }
 
 
 void Process::TerminateExitCodeHandler() {
   ExitCodeHandler::TerminateExitCodeThread();
 }
 
 
 intptr_t Process::CurrentProcessId() {
   return static_cast<intptr_t>(getpid());
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_LINUX)