From abf99aad2d70e680cdfe0ad72842c9b10e50045a Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Sun, 20 May 2012 20:29:22 +0000
Subject: [PATCH] Implement wxStackWalker for wxOSX.

Use atos(1) to map address to their symbolic names.

Closes #10067.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@71513 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
---
 docs/changes.txt         |   1 +
 include/wx/osx/chkconf.h |   7 ---
 src/unix/stackwalk.cpp   | 127 +++++++++++++++++++++++++++------------
 3 files changed, 91 insertions(+), 44 deletions(-)

diff --git a/docs/changes.txt b/docs/changes.txt
index dda32f3a95..84a8530d22 100644
--- a/docs/changes.txt
+++ b/docs/changes.txt
@@ -581,6 +581,7 @@ OSX:
 
 - Provide native implementations of wxDatePickerCtrl and wxTimePickerCtrl.
 - Fix handling of positional parameters in wxPrintf() &c (David Connet).
+- Implement wxStackWalker.
 
 Univ:
 
diff --git a/include/wx/osx/chkconf.h b/include/wx/osx/chkconf.h
index 98e950215f..1b56ac8981 100644
--- a/include/wx/osx/chkconf.h
+++ b/include/wx/osx/chkconf.h
@@ -14,13 +14,6 @@
 #ifndef _WX_OSX_CHKCONF_H_
 #define _WX_OSX_CHKCONF_H_
 
-
-#if wxUSE_STACKWALKER
-    /* not supported under Mac */
-#   undef wxUSE_STACKWALKER
-#   define wxUSE_STACKWALKER 0
-#endif /* wxUSE_STACKWALKER */
-
 /*
  * check graphics context option, must be on for every os x platform
  * we only use core graphics now on all builds, try to catch attempts
diff --git a/src/unix/stackwalk.cpp b/src/unix/stackwalk.cpp
index 6c234adbea..f724816e9c 100644
--- a/src/unix/stackwalk.cpp
+++ b/src/unix/stackwalk.cpp
@@ -130,10 +130,12 @@ void wxStackFrame::OnGetName()
 
         m_module.assign(syminfo, posOpen);
     }
+#ifndef __WXOSX__
     else // not in "module(funcname+offset)" format
     {
         m_module = syminfo;
     }
+#endif // !__WXOSX__
 }
 
 
@@ -204,6 +206,28 @@ void wxStackWalker::FreeStack()
     m_depth = 0;
 }
 
+namespace
+{
+
+// Helper function to read a line from the file and return it without the
+// trailing newline. Line number is only used for error reporting.
+bool ReadLine(FILE* fp, unsigned long num, wxString* line)
+{
+    if ( !fgets(g_buf, WXSIZEOF(g_buf), fp) )
+    {
+        wxLogDebug(wxS("cannot read address information for stack frame #%lu"),
+                   num);
+        return false;
+    }
+
+    *line = wxString::FromAscii(g_buf);
+    line->RemoveLast();
+
+    return true;
+}
+
+} // anonymous namespace
+
 int wxStackWalker::InitFrames(wxStackFrame *arr, size_t n, void **addresses, char **syminfo)
 {
     // we need to launch addr2line tool to get this information and we need to
@@ -220,9 +244,13 @@ int wxStackWalker::InitFrames(wxStackFrame *arr, size_t n, void **addresses, cha
         }
     }
 
-    // build the (long) command line for executing addr2line in an optimized way
-    // (e.g. use always chars, even in Unicode build: popen() always takes chars)
+    // build the command line for executing addr2line or atos under OS X using
+    // char* directly to avoid the conversions from Unicode
+#ifdef __WXOSX__
+    int len = snprintf(g_buf, BUFSIZE, "atos -p %d", (int)getpid());
+#else
     int len = snprintf(g_buf, BUFSIZE, "addr2line -C -f -e \"%s\"", (const char*) exepath.mb_str());
+#endif
     len = (len <= 0) ? strlen(g_buf) : len;     // in case snprintf() is broken
     for (size_t i=0; i<n; i++)
     {
@@ -236,54 +264,79 @@ int wxStackWalker::InitFrames(wxStackFrame *arr, size_t n, void **addresses, cha
     if ( !fp )
         return 0;
 
-    // parse addr2line output (should be exactly 2 lines for each address)
-    // reusing the g_buf used for building the command line above
+    // parse the output reusing the same buffer to avoid any big memory
+    // allocations which could fail if our program is in a bad state
     wxString name, filename;
     unsigned long line = 0,
                   curr = 0;
     for  ( size_t i = 0; i < n; i++ )
     {
-        // 1st line has function name
-        if ( fgets(g_buf, WXSIZEOF(g_buf), fp) )
+#ifdef __WXOSX__
+        wxString buffer;
+        if ( !ReadLine(fp, i, &buffer) )
+            return false;
+
+        line = 0;
+        filename.clear();
+
+        // We can get back either the string in the following format:
+        //
+        //      func(args) (in module) (file:line)
+        //
+        // or just the same address back if it couldn't be resolved.
+        const size_t posIn = buffer.find("(in ");
+        if ( posIn != wxString::npos )
         {
-            name = wxString::FromAscii(g_buf);
-            name.RemoveLast(); // trailing newline
+            name.assign(buffer, 0, posIn);
+
+            size_t posAt = buffer.find(") (", posIn + 3);
+            if ( posAt != wxString::npos )
+            {
+                posAt += 3; // Skip ") ("
+
+                // Discard the two last characters which are ")\n"
+                wxString location(buffer, posAt, buffer.length() - posAt - 2);
 
-            if ( name == wxT("??") )
-                name.clear();
+                wxString linenum;
+                filename = location.BeforeFirst(':', &linenum);
+                if ( !linenum.empty() )
+                    linenum.ToULong(&line);
+            }
         }
-        else
-        {
-            wxLogDebug(wxT("cannot read addr2line output for stack frame #%lu"),
-                       (unsigned long)i);
+#else // !__WXOSX__
+        // 1st line has function name
+        if ( !ReadLine(fp, i, &name) )
             return false;
-        }
+
+        name = wxString::FromAscii(g_buf);
+        name.RemoveLast(); // trailing newline
+
+        if ( name == wxT("??") )
+            name.clear();
 
         // 2nd one -- the file/line info
-        if ( fgets(g_buf, WXSIZEOF(g_buf), fp) )
-        {
-            filename = wxString::FromAscii(g_buf);
-            filename.RemoveLast();
+        if ( !ReadLine(fp, i, &filename) )
+            return false;
 
-            const size_t posColon = filename.find(wxT(':'));
-            if ( posColon != wxString::npos )
-            {
-                // parse line number (it's ok if it fails, this will just leave
-                // line at its current, invalid, 0 value)
-                wxString(filename, posColon + 1, wxString::npos).ToULong(&line);
-
-                // remove line number from 'filename'
-                filename.erase(posColon);
-                if ( filename == wxT("??") )
-                    filename.clear();
-            }
-            else
-            {
-                wxLogDebug(wxT("Unexpected addr2line format: \"%s\" - ")
-                           wxT("the semicolon is missing"),
-                           filename.c_str());
-            }
+        const size_t posColon = filename.find(wxT(':'));
+        if ( posColon != wxString::npos )
+        {
+            // parse line number (it's ok if it fails, this will just leave
+            // line at its current, invalid, 0 value)
+            wxString(filename, posColon + 1, wxString::npos).ToULong(&line);
+
+            // remove line number from 'filename'
+            filename.erase(posColon);
+            if ( filename == wxT("??") )
+                filename.clear();
+        }
+        else
+        {
+            wxLogDebug(wxT("Unexpected addr2line format: \"%s\" - ")
+                       wxT("the semicolon is missing"),
+                       filename.c_str());
         }
+#endif // __WXOSX__/!__WXOSX__
 
         // now we've got enough info to initialize curr-th stack frame
         // (at worst, only addresses[i] and syminfo[i] have been initialized,
-- 
2.45.2