First part of work for #4498. This change forces each CEF instance to have it's own cache/cookie folder underneath the parent cef_cache folder. The whole cef_cache folder structure is purged at startup (before the parent being created at the first media instance creation)

indra/media_plugins/cef/media_plugin_cef.cpp

@@ -38,6 +38,13 @@
 #include "volume_catcher.h"
 #include "media_plugin_base.h"
 
+// _getpid()/getpid()
+#if LL_WINDOWS
+#include <process.h>
+#else
+#include <unistd.h>
+#endif
+
 #include "dullahan.h"
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -729,17 +736,34 @@ void MediaPluginCEF::receiveMessage(const char* message_string)
                 std::string user_data_path_cache = message_in.getValue("cache_path");
                 std::string subfolder = message_in.getValue("username");
 
+                // media plugin doesn't have access to gDirUtilp
+                std::string path_separator;
+#if LL_WINDOWS
+                path_separator = "\\";
+#else
+                path_separator = "/";
+#endif
+
                 mRootCachePath = user_data_path_cache + "cef_cache";
+
+                // Issue #4498 Introduce an additional sub-folder underneath the main cache
+                // folder so that each CEF media instance gets its own (as per the CEF API
+                // official position). These folders will be removed at startup by Viewer code
+                // so that their non-trivial size does not exhaust available disk space. This
+                // begs the question - why turn on the cache at all? There are 2 reasons - firstly
+                // some of the instances will benefit from per Viewer session caching and will
+                // use the injected SL cookie and secondly, it's not clear how having no cache
+                // interacts with the multiple simultaneous paradigm we use.
+                mRootCachePath += path_separator;
+# if LL_WINDOWS
+                mRootCachePath += std::to_string(_getpid());
+# else
+                mRootCachePath += std::to_string(getpid());
+# endif
+
                 if (!subfolder.empty())
                 {
-                    std::string delim;
-#if LL_WINDOWS
-                    // media plugin doesn't have access to gDirUtilp
-                    delim = "\\";
-#else
-                    delim = "/";
-#endif
-                    mCachePath = mRootCachePath + delim + subfolder;
+                    mCachePath = mRootCachePath + path_separator + subfolder;
                 }
                 else
                 {

indra/newview/llappviewer.cpp

@@ -4411,6 +4411,9 @@ bool LLAppViewer::initCache()
     const U32 CACHE_NUMBER_OF_REGIONS_FOR_OBJECTS = 128;
     LLVOCache::getInstance()->initCache(LL_PATH_CACHE, CACHE_NUMBER_OF_REGIONS_FOR_OBJECTS, getObjectCacheVersion());
 
+    // Remove old, stale CEF cache folders
+    purgeCefStaleCaches();
+
     return true;
 }
 
@@ -4435,18 +4438,27 @@ void LLAppViewer::loadKeyBindings()
     LLUrlRegistry::instance().setKeybindingHandler(&gViewerInput);
 }
 
+// As per GHI #4498, remove old, stale CEF cache folders from previous sessions
+void LLAppViewer::purgeCefStaleCaches()
+{
+    // TODO: we really shouldn't use a hard coded name for the cache folder here...
+    const std::string browser_parent_cache = gDirUtilp->getExpandedFilename(LL_PATH_CACHE, "cef_cache");
+    if (LLFile::isdir(browser_parent_cache))
+    {
+        // This is a sledgehammer approach - nukes the cef_cache dir entirely
+        // which is then recreated the first time a CEF instance creates an
+        // individual cache folder. If we ever decide to retain some folders
+        // e.g. Search UI cache - then we will need a more granular approach.
+        gDirUtilp->deleteDirAndContents(browser_parent_cache);
+    }
+}
+
 void LLAppViewer::purgeCache()
 {
     LL_INFOS("AppCache") << "Purging Cache and Texture Cache..." << LL_ENDL;
     LLAppViewer::getTextureCache()->purgeCache(LL_PATH_CACHE);
     LLVOCache::getInstance()->removeCache(LL_PATH_CACHE);
     LLViewerShaderMgr::instance()->clearShaderCache();
-    std::string browser_cache = gDirUtilp->getExpandedFilename(LL_PATH_CACHE, "cef_cache");
-    if (LLFile::isdir(browser_cache))
-    {
-        // cef does not support clear_cache and clear_cookies, so clear what we can manually.
-        gDirUtilp->deleteDirAndContents(browser_cache);
-    }
     gDirUtilp->deleteFilesInDir(gDirUtilp->getExpandedFilename(LL_PATH_CACHE, ""), "*");
 }
 

indra/newview/llappviewer.h

@@ -220,6 +220,7 @@ public:
 
     void initGeneralThread();
     void purgeUserDataOnExit() { mPurgeUserDataOnExit = true; }
+    void purgeCefStaleCaches();  // Remove old, stale CEF cache folders
     void purgeCache(); // Clear the local cache.
     void purgeCacheImmediate(); //clear local cache immediately.
     S32  updateTextureThreads(F32 max_time);