Bug 1109291 - Include better paths for hanging chrome scripts in profile extensions directory; r=snorp r=bsmedberg

xpcom/threads/ThreadStackHelper.cpp

@@ -541,6 +541,8 @@ IsChromeJSScript(JSScript* aScript)
   return secman->IsSystemPrincipal(nsJSPrincipals::get(principals));
 }
 
+// Get the full path after the URI scheme, if the URI matches the scheme.
+// For example, GetFullPathForScheme("a://b/c/d/e", "a://") returns "b/c/d/e".
 template <size_t LEN>
 const char*
 GetFullPathForScheme(const char* filename, const char (&scheme)[LEN]) {
@@ -551,6 +553,23 @@ GetFullPathForScheme(const char* filename, const char (&scheme)[LEN]) {
   return nullptr;
 }
 
+// Get the full path after a URI component, if the URI contains the component.
+// For example, GetPathAfterComponent("a://b/c/d/e", "/c/") returns "d/e".
+template <size_t LEN>
+const char*
+GetPathAfterComponent(const char* filename, const char (&component)[LEN]) {
+  const char* found = nullptr;
+  const char* next = strstr(filename, component);
+  while (next) {
+    // Move 'found' to end of the component, after the separator '/'.
+    // 'LEN - 1' accounts for the null terminator included in LEN,
+    found = next + LEN - 1;
+    // Resume searching before the separator '/'.
+    next = strstr(found - 1, component);
+  }
+  return found;
+}
+
 } // namespace
 
 const char*
@@ -566,19 +585,30 @@ ThreadStackHelper::AppendJSEntry(const volatile StackEntry* aEntry,
 
   const char* label;
   if (IsChromeJSScript(aEntry->script())) {
-    const char* const filename = JS_GetScriptFilename(aEntry->script());
-    unsigned lineno = JS_PCToLineNumber(aEntry->script(), aEntry->pc());
+    const char* filename = JS_GetScriptFilename(aEntry->script());
+    const unsigned lineno = JS_PCToLineNumber(aEntry->script(), aEntry->pc());
     MOZ_ASSERT(filename);
 
-    char buffer[64]; // Enough to fit longest js file name from the tree
-    const char* basename;
+    char buffer[128]; // Enough to fit longest js file name from the tree
+
+    // Some script names are in the form "foo -> bar -> baz".
+    // Here we find the origin of these redirected scripts.
+    const char* basename = GetPathAfterComponent(filename, " -> ");
+    if (basename) {
+      filename = basename;
+    }
 
     basename = GetFullPathForScheme(filename, "chrome://");
     if (!basename) {
       basename = GetFullPathForScheme(filename, "resource://");
     }
     if (!basename) {
-      // Only keep the file base name for paths not under the above schemes.
+      // If the (add-on) script is located under the {profile}/extensions
+      // directory, extract the path after the /extensions/ part.
+      basename = GetPathAfterComponent(filename, "/extensions/");
+    }
+    if (!basename) {
+      // Only keep the file base name for paths outside the above formats.
       basename = strrchr(filename, '/');
       basename = basename ? basename + 1 : filename;
     }