Changeset 91627 in webkit for trunk/Source/JavaScriptCore/API/JSContextRef.cpp

Timestamp:

Jul 22, 2011, 5:19:05 PM (14 years ago)

Author:

[email protected]

Message:

Patch by Sommer Panage <​[email protected]> on 2011-07-22
Reviewed by Oliver Hunt.

export JSContextCreateBacktrace as SPI in JSContextRefPrivate.h
​https://bugs.webkit.org/show_bug.cgi?id=64981

UIAutomation for iOS would like to support a Javascript backtrace in our error logs.
Currently, the C API does not provide the tools to do this. However, the private API
does expose the necessary functionality to get a backtrace
(via Interpreter::retrieveLastCaller). We recognize this information may result in
failure in the cases of programs run by 'eval', stack frames beneath host function
call frames, and in programs run from other programs. Thus, we propose exporting our
JSContextCreateBacktrace in JSContextRefPrivate.h. This will provide us with the tools
we need while not advertising an API that isn't really ready for full use.

• API/JSContextRef.cpp:
• API/JSContextRefPrivate.h:
• JavaScriptCore.exp:

File:

• trunk/Source/JavaScriptCore/API/JSContextRef.cpp (modified) (2 diffs)

trunk/Source/JavaScriptCore/API/JSContextRef.cpp

@@ -30 +30 @@
 #include "APICast.h"
 #include "InitializeThreading.h"
+#include <interpreter/CallFrame.h>
+#include <interpreter/Interpreter.h>
 #include "JSCallbackObject.h"
 #include "JSClassRef.h"
 #include "JSGlobalObject.h"
 #include "JSObject.h"
+#include "UStringBuilder.h"
 #include <wtf/text/StringHash.h>
+
 
 #if OS(DARWIN)
@@ -178 +182 @@
     return toGlobalRef(exec->lexicalGlobalObject()->globalExec());
 }
+    
+JSStringRef JSContextCreateBacktrace(JSContextRef ctx, unsigned maxStackSize)
+{
+    ExecState* exec = toJS(ctx);
+    JSLock lock(exec);
+
+    unsigned count = 0;
+    UStringBuilder builder;
+    CallFrame* callFrame = exec;
+    UString functionName;
+    if (exec->callee()) {
+        if (asObject(exec->callee())->inherits(&InternalFunction::s_info)) {
+            functionName = asInternalFunction(exec->callee())->name(exec);
+            builder.append("#0 ");
+            builder.append(functionName);
+            builder.append("() ");
+            count++;
+        }
+    }
+    while (true) {
+        ASSERT(callFrame);
+        int signedLineNumber;
+        intptr_t sourceID;
+        UString urlString;
+        JSValue function;
+        
+        UString levelStr = UString::number(count);
+        
+        exec->interpreter()->retrieveLastCaller(callFrame, signedLineNumber, sourceID, urlString, function);
+
+        if (function)
+            functionName = asFunction(function)->name(exec);
+        else {
+            // Caller is unknown, but if frame is empty we should still add the frame, because
+            // something called us, and gave us arguments.
+            if (count)
+                break;
+        }
+        unsigned lineNumber = signedLineNumber >= 0 ? signedLineNumber : 0;
+        if (!builder.isEmpty())
+            builder.append("\n");
+        builder.append("#");
+        builder.append(levelStr);
+        builder.append(" ");
+        builder.append(functionName);
+        builder.append("() at ");
+        builder.append(urlString);
+        builder.append(":");
+        builder.append(UString::number(lineNumber));
+        if (!function || ++count == maxStackSize)
+            break;
+        callFrame = callFrame->callerFrame();
+    }
+    return OpaqueJSString::create(builder.toUString()).leakRef();
+}
+
+