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diff --git a/src/stream.cc b/src/stream.cc
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+/*
+ * Copyright (c) 2003-2009, John Wiegley.  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 with the distribution.
+ *
+ * - Neither the name of New Artisans LLC nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * 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 <system.hh>
+
+#include "stream.h"
+
+namespace ledger {
+
+namespace {
+  /**
+   * @brief Forks a child process so that Ledger may handle running a
+   * pager
+   *
+   * In order for the pager option to work, Ledger has to run the pager
+   * itself, which requires Ledger to fork a new process in order to run
+   * the pager.  This function does the necessary fork.  After the fork,
+   * two processes exist.  One of them is exec'd to create the pager;
+   * the other is still Ledger.
+   *
+   * This function returns only for the process that is still Ledger.
+   *
+   * @param out Pointer to a pointer to the output stream.  This The
+   * pointer to the output stream is changed so that the stream is
+   * connected to the stdin of the pager.  The caller is responsible for
+   * cleaning this up.
+   *
+   * @param pager_path Path to the pager command.
+   *
+   * @return The file descriptor of the pipe to the pager.  The caller
+   * is responsible for cleaning this up.
+   *
+   * @exception std::logic_error Some problem was encountered, such as
+   * failure to create a pipe or failure to fork a child process.
+   */
+  int do_fork(std::ostream ** os, const path& pager_path)
+  {
+    int pfd[2];
+
+    int status = pipe(pfd);
+    if (status == -1)
+      throw std::logic_error(_("Failed to create pipe"));
+
+    status = fork();
+    if (status < 0) {
+      throw std::logic_error(_("Failed to fork child process"));
+    }
+    else if (status == 0) {	// child
+      // Duplicate pipe's reading end into stdin
+      status = dup2(pfd[0], STDIN_FILENO);
+      if (status == -1)
+	perror("dup2");
+
+      // Close unuseful file descriptors: the pipe's writing and reading
+      // ends (the latter is not needed anymore, after the duplication).
+      close(pfd[1]);
+      close(pfd[0]);
+
+      // Find command name: its the substring starting right of the
+      // rightmost '/' character in the pager pathname.  See manpage for
+      // strrchr.
+#if BOOST_VERSION >= 103700
+      path basename(pager_path.filename());
+#else
+      path basename(pager_path.leaf());
+#endif
+      execlp(pager_path.string().c_str(), basename.string().c_str(), NULL);
+
+      // We should never, ever reach here
+      perror((std::string("execlp: ") + pager_path.string()).c_str());
+      exit(1);
+    }
+    else {			// parent
+      close(pfd[0]);
+      typedef iostreams::stream<iostreams::file_descriptor_sink> fdstream;
+      *os = new fdstream(pfd[1]);
+    }
+    return pfd[1];
+  }
+}
+
+void output_stream_t::initialize(const optional<path>& output_file,
+				 const optional<path>& pager_path)
+{
+  if (output_file && *output_file != "-")
+    os = new ofstream(*output_file);
+  else if (pager_path)
+    pipe_to_pager_fd = do_fork(&os, *pager_path);
+  else
+    os = &std::cout;
+}
+
+void output_stream_t::close()
+{
+  if (os != &std::cout) {
+    checked_delete(os);
+    os = &std::cout;
+  }
+
+  if (pipe_to_pager_fd != -1) {
+    ::close(pipe_to_pager_fd);
+    pipe_to_pager_fd = -1;
+
+    int status;
+    wait(&status);
+    if (! WIFEXITED(status) || WEXITSTATUS(status) != 0)
+      throw std::logic_error(_("Error in the pager"));
+  }
+}
+
+} // namespace ledger