From 81abf8eab067eab362f180a418215f9408de41dc Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Fri, 4 Sep 2015 14:15:37 +0200
Subject: Add support for printing process command line

---
 bpkg/diagnostics     | 31 ++++++++++++++++++++++++++++++-
 bpkg/diagnostics.cxx | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/bpkg/diagnostics b/bpkg/diagnostics
index 85eef2b..af9bde0 100644
--- a/bpkg/diagnostics
+++ b/bpkg/diagnostics
@@ -17,11 +17,41 @@
 
 namespace bpkg
 {
+  struct diag_record;
+
   // Throw this exception to terminate the process. The handler should
   // assume that the diagnostics has already been issued.
   //
   class failed: public std::exception {};
 
+  // Print process commmand line. If the number of elements is specified
+  // (or the second version is used), then it will print the piped multi-
+  // process command line, if present. In this case, the expected format
+  // is as follows:
+  //
+  // name1 arg arg ... nullptr
+  // name2 arg arg ... nullptr
+  // ...
+  // nameN arg arg ... nullptr nullptr
+  //
+  void
+  print_process (diag_record&, const char* const* args, std::size_t n = 0);
+
+  void
+  print_process (const char* const* args, std::size_t n = 0);
+
+  inline void
+  print_process (diag_record& dr, const cstrings& args)
+  {
+    print_process (dr, args.data (), args.size ());
+  }
+
+  inline void
+  print_process (const cstrings& args)
+  {
+    print_process (args.data (), args.size ());
+  }
+
   // Trace verbosity level.
   //
   // 0 - tracing disabled.
@@ -45,7 +75,6 @@ namespace bpkg
   //
   extern std::ostream* diag_stream;
 
-  struct diag_record;
   template <typename> struct diag_prologue;
   template <typename> struct diag_mark;
 
diff --git a/bpkg/diagnostics.cxx b/bpkg/diagnostics.cxx
index 2bee18e..4c5e24b 100644
--- a/bpkg/diagnostics.cxx
+++ b/bpkg/diagnostics.cxx
@@ -10,6 +10,40 @@ using namespace std;
 
 namespace bpkg
 {
+  // print_process
+  //
+  void
+  print_process (const char* const* args, size_t n)
+  {
+    diag_record r (text);
+    print_process (r, args, n);
+  }
+
+  void
+  print_process (diag_record& r, const char* const* args, size_t n)
+  {
+    size_t m (0);
+    const char* const* p (args);
+    do
+    {
+      if (m != 0)
+        r << " |"; // Trailing space will be added inside the loop.
+
+      for (m++; *p != nullptr; p++, m++)
+        r << (p != args ? " " : "")
+          << (**p == '\0' ? "\"" : "") // Quote empty arguments.
+          << *p
+          << (**p == '\0' ? "\"" : "");
+
+      if (m < n) // Can we examine the next element?
+      {
+        p++;
+        m++;
+      }
+
+    } while (*p != nullptr);
+  }
+
   // Trace verbosity level.
   //
   uint16_t verb;
-- 
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