From c47718b2da10f3546b54b4e1001bb5ebe76227df Mon Sep 17 00:00:00 2001
From: Hans-Peter Deifel <hpdeifel@gmx.de>
Date: Fri, 12 Dec 2014 13:09:51 +0100
Subject: [PATCH] cpp: New API to set debug output function

Adds the global function set_debug_error_function, that allows users
to install their own function to print internal poppler errors.
---
 cpp/poppler-global.cpp  | 28 ++++++++++++++++++++++++++++
 cpp/poppler-global.h    |  4 ++++
 cpp/poppler-private.cpp | 14 +++++++++++---
 cpp/poppler-private.h   |  2 ++
 4 files changed, 45 insertions(+), 3 deletions(-)

diff --git a/cpp/poppler-global.cpp b/cpp/poppler-global.cpp
index 176c0c8..e95c428 100644
--- a/cpp/poppler-global.cpp
+++ b/cpp/poppler-global.cpp
@@ -334,3 +334,31 @@ std::ostream& poppler::operator<<(std::ostream& stream, const byte_array &array)
     stream << "]";
     return stream;
 }
+
+/**
+ \typedef poppler::debug_func
+
+ Debug/error function.
+
+ This function type is used for debugging & error output;
+ the first parameter is the actual message, the second is the unaltered
+ closure argument which was passed to the set_debug_error_function() call.
+
+ \since 0.30.0
+ */
+
+/**
+ Set a new debug/error output function.
+
+ If not set, by default error and debug messages will be sent to stderr.
+
+ \param debug_function the new debug function
+ \param closure user data which will be passed as-is to the debug function
+
+ \since 0.30.0
+ */
+void poppler::set_debug_error_function(debug_func debug_function, void *closure)
+{
+    poppler::detail::user_debug_function = debug_function;
+    poppler::detail::debug_closure = closure;
+}
diff --git a/cpp/poppler-global.h b/cpp/poppler-global.h
index 5650182..157aaf9 100644
--- a/cpp/poppler-global.h
+++ b/cpp/poppler-global.h
@@ -106,6 +106,10 @@ POPPLER_CPP_EXPORT time_type convert_date(const std::string &date);
 
 POPPLER_CPP_EXPORT std::ostream& operator<<(std::ostream& stream, const byte_array &array);
 
+typedef void(*debug_func)(const std::string &, void *);
+
+POPPLER_CPP_EXPORT void set_debug_error_function(debug_func debug_function, void *closure);
+
 }
 
 #endif
diff --git a/cpp/poppler-private.cpp b/cpp/poppler-private.cpp
index 3bee619..ed8d381 100644
--- a/cpp/poppler-private.cpp
+++ b/cpp/poppler-private.cpp
@@ -29,16 +29,24 @@
 
 using namespace poppler;
 
+static void stderr_debug_function(const std::string &msg, void * /*data*/)
+{
+    std::cerr << "poppler/" << msg;
+}
+
+debug_func detail::user_debug_function = stderr_debug_function;
+void *detail::debug_closure;
+
 void detail::error_function(void * /*data*/, ErrorCategory /*category*/, Goffset pos, char *msg)
 {
     std::ostringstream oss;
     if (pos >= 0) {
-        oss << "poppler/error (" << pos << "): ";
+        oss << "error (" << pos << "): ";
     } else {
-        oss << "poppler/error: ";
+        oss << "error: ";
     }
     oss << msg;
-    std::cerr << oss.str();
+    detail::user_debug_function(oss.str(), detail::debug_closure);
 }
 
 rectf detail::pdfrectangle_to_rectf(const PDFRectangle &pdfrect)
diff --git a/cpp/poppler-private.h b/cpp/poppler-private.h
index 3e8873f..6dfdd61 100644
--- a/cpp/poppler-private.h
+++ b/cpp/poppler-private.h
@@ -39,6 +39,8 @@ namespace poppler
 namespace detail
 {
 
+extern debug_func user_debug_function;
+extern void *debug_closure;
 void error_function(void *data, ErrorCategory category, Goffset pos, char *msg);
 
 rectf pdfrectangle_to_rectf(const PDFRectangle &pdfrect);
-- 
2.0.4