1 files changed, 39 insertions, 36 deletions

diff --git a/components/jar/src/nsJARChannel.cpp b/components/jar/src/nsJARChannel.cpp
index 65c034779..0bbfa31eb 100644
--- a/components/jar/src/nsJARChannel.cpp
+++ b/components/jar/src/nsJARChannel.cpp
@@ -577,48 +577,47 @@ nsJARChannel::GetSecurityInfo(nsISupports **aSecurityInfo)
     return NS_OK;
 }
 
+bool nsJARChannel::GetContentTypeGuess(nsACString& aResult) const {
+  const char *ext = nullptr, *fileName = mJarEntry.get();
+  int32_t len = mJarEntry.Length();
+
+  // check if we're displaying a directory
+  // mJarEntry will be empty if we're trying to display
+  // the topmost directory in a zip, e.g. jar:foo.zip!/
+  if (ENTRY_IS_DIRECTORY(mJarEntry)) {
+    aResult.AssignLiteral(APPLICATION_HTTP_INDEX_FORMAT);
+    return true;
+  }
+
+  // Not a directory, take a guess by its extension
+  for (int32_t i = len - 1; i >= 0; i--) {
+    if (fileName[i] == '.') {
+      ext = &fileName[i + 1];
+      break;
+    }
+  }
+  if (!ext) {
+    return false;
+  }
+  nsIMIMEService* mimeServ = gJarHandler->MimeService();
+  if (!mimeServ) {
+    return false;
+  }
+  mimeServ->GetTypeFromExtension(nsDependentCString(ext), aResult);
+  return !aResult.IsEmpty();
+}
+
 NS_IMETHODIMP
-nsJARChannel::GetContentType(nsACString &result)
+nsJARChannel::GetContentType(nsACString &aResult)
 {
     // If the Jar file has not been open yet,
     // We return application/x-unknown-content-type
     if (!mOpened) {
-      result.Assign(UNKNOWN_CONTENT_TYPE);
+      aResult.Assign(UNKNOWN_CONTENT_TYPE);
       return NS_OK;
     }
 
-    if (mContentType.IsEmpty()) {
-
-        //
-        // generate content type and set it
-        //
-        const char *ext = nullptr, *fileName = mJarEntry.get();
-        int32_t len = mJarEntry.Length();
-
-        // check if we're displaying a directory
-        // mJarEntry will be empty if we're trying to display
-        // the topmost directory in a zip, e.g. jar:foo.zip!/
-        if (ENTRY_IS_DIRECTORY(mJarEntry)) {
-            mContentType.AssignLiteral(APPLICATION_HTTP_INDEX_FORMAT);
-        }
-        else {
-            // not a directory, take a guess by its extension
-            for (int32_t i = len-1; i >= 0; i--) {
-                if (fileName[i] == '.') {
-                    ext = &fileName[i + 1];
-                    break;
-                }
-            }
-            if (ext) {
-                nsIMIMEService *mimeServ = gJarHandler->MimeService();
-                if (mimeServ)
-                    mimeServ->GetTypeFromExtension(nsDependentCString(ext), mContentType);
-            }
-            if (mContentType.IsEmpty())
-                mContentType.AssignLiteral(UNKNOWN_CONTENT_TYPE);
-        }
-    }
-    result = mContentType;
+    aResult = mContentType;
     return NS_OK;
 }
 
@@ -636,8 +635,8 @@ nsJARChannel::SetContentType(const nsACString &aContentType)
 NS_IMETHODIMP
 nsJARChannel::GetContentCharset(nsACString &aContentCharset)
 {
-    // If someone gives us a charset hint we should just use that charset.
-    // So we don't care when this is being called.
+    // We behave like HTTP channels (treat this as a hint if called before open,
+    // and override the charset if called after open).
     aContentCharset = mContentCharset;
     return NS_OK;
 }
@@ -730,6 +729,10 @@ nsJARChannel::Open(nsIInputStream **stream)
 
     input.forget(stream);
     mOpened = true;
+    // Compute the content type now.
+    if (!GetContentTypeGuess(mContentType)) {
+        mContentType.Assign(UNKNOWN_CONTENT_TYPE);
+    }
     // local files are always considered safe
     mIsUnsafe = false;
     return NS_OK;