From 567cc5b7df491a8828abb9a78c1bd64b710e9163 Mon Sep 17 00:00:00 2001
From: Byron Milligan <bmilligan@mozilla.com>
Date: Wed, 8 Sep 2010 17:49:17 -0700
Subject: [PATCH] Bug 559942: Set cache size based on disk space available.
 Synchronous. r=jduell, a=beta6+

---
 browser/components/preferences/advanced.xul | 111 ++++++++-------
 netwerk/cache/nsCacheService.cpp            | 147 ++++++++++++++++++++
 2 files changed, 202 insertions(+), 56 deletions(-)

diff --git a/browser/components/preferences/advanced.xul b/browser/components/preferences/advanced.xul
index fabbf422688c..10019877262b 100644
--- a/browser/components/preferences/advanced.xul
+++ b/browser/components/preferences/advanced.xul
@@ -217,65 +217,64 @@
         <!-- Network -->
         <tabpanel id="networkPanel" orient="vertical">
 
-           <!-- Connection -->
-           <groupbox id="connectionGroup">
-             <caption label="&connection.label;"/>
+          <!-- Connection -->
+          <groupbox id="connectionGroup">
+            <caption label="&connection.label;"/>
 
-             <hbox align="center">
-               <description flex="1" control="connectionSettings">&connectionDesc.label;</description>
-               <button id="connectionSettings" icon="network" label="&connectionSettings.label;"
-                       accesskey="&connectionSettings.accesskey;"
-                       oncommand="gAdvancedPane.showConnections();"/>
-             </hbox>
-           </groupbox>
+            <hbox align="center">
+              <description flex="1" control="connectionSettings">&connectionDesc.label;</description>
+              <button id="connectionSettings" icon="network" label="&connectionSettings.label;"
+                      accesskey="&connectionSettings.accesskey;"
+                      oncommand="gAdvancedPane.showConnections();"/>
+            </hbox>
+          </groupbox>
 
-           <!-- Cache/Offline apps -->
-           <groupbox id="offlineGroup">
-             <caption label="&offlineStorage.label;"/>
+          <!-- Cache/Offline apps -->
+          <groupbox id="offlineGroup">
+            <caption label="&offlineStorage.label;"/>
 
-             <hbox align="center">
-               <label id="useCacheBefore" control="cacheSize"
-                      accesskey="&useCacheBefore.accesskey;" value="&useCacheBefore.label;"/>
-               <textbox id="cacheSize" type="number" size="2"
-                        preference="browser.cache.disk.capacity"
-                        onsyncfrompreference="return gAdvancedPane.readCacheSize();"
-                        onsynctopreference="return gAdvancedPane.writeCacheSize();"
-                        aria-labelledby="useCacheBefore cacheSize useCacheAfter"/>
-               <label id="useCacheAfter" flex="1">&useCacheAfter.label;</label>
-               <button id="clearCacheButton" icon="clear"
-                       label="&clearCacheNow.label;" accesskey="&clearCacheNow.accesskey;"
-                       oncommand="gAdvancedPane.clearCache();"/>
-             </hbox>
-	     <hbox align="center">
-	       <checkbox id="offlineNotify" flex="1"
-			 label="&offlineNotify.label;" accesskey="&offlineNotify.accesskey;"
-			 preference="browser.offline-apps.notify"
-			 onsyncfrompreference="return gAdvancedPane.readOfflineNotify();"/>
-	       <button id="offlineNotifyExceptions"
-		       label="&offlineNotifyExceptions.label;"
-		       accesskey="&offlineNotifyExceptions.accesskey;"
-		       oncommand="gAdvancedPane.showOfflineExceptions();"/>
-	     </hbox>
-	     <hbox>
-	       <vbox flex="1">
-
-		 <label id="offlineAppsListLabel">&offlineAppsList.label;</label>
-		 <listbox id="offlineAppsList"
-			  style="height: &offlineAppsList.height;;"
-			  flex="1"
-			  aria-labelledby="offlineAppsListLabel"
-			  onselect="gAdvancedPane.offlineAppSelected(event);">
-		 </listbox>
-	       </vbox>
-	       <vbox pack="end">
-		 <button id="offlineAppsListRemove"
-			 disabled="true"
-			 label="&offlineAppsListRemove.label;"
-			 accesskey="&offlineAppsListRemove.accesskey;" 
-			 oncommand="gAdvancedPane.removeOfflineApp();"/>
-	       </vbox>
-	     </hbox>
-	   </groupbox>
+            <hbox align="center">
+              <label id="useCacheBefore" control="cacheSize"
+                     accesskey="&useCacheBefore.accesskey;" value="&useCacheBefore.label;"/>
+              <textbox id="cacheSize" type="number" size="2"
+                       preference="browser.cache.disk.capacity"
+                       onsyncfrompreference="return gAdvancedPane.readCacheSize();"
+                       onsynctopreference="return gAdvancedPane.writeCacheSize();"
+                       aria-labelledby="useCacheBefore cacheSize useCacheAfter"/>
+              <label id="useCacheAfter" flex="1">&useCacheAfter.label;</label>
+              <button id="clearCacheButton" icon="clear"
+                      label="&clearCacheNow.label;" accesskey="&clearCacheNow.accesskey;"
+                      oncommand="gAdvancedPane.clearCache();"/>
+            </hbox>
+            <hbox align="center">
+              <checkbox id="offlineNotify" flex="1"
+                        label="&offlineNotify.label;" accesskey="&offlineNotify.accesskey;"
+                        preference="browser.offline-apps.notify"
+                        onsyncfrompreference="return gAdvancedPane.readOfflineNotify();"/>
+              <button id="offlineNotifyExceptions"
+                      label="&offlineNotifyExceptions.label;"
+                      accesskey="&offlineNotifyExceptions.accesskey;"
+                      oncommand="gAdvancedPane.showOfflineExceptions();"/>
+            </hbox>
+            <hbox>
+              <vbox flex="1">
+                <label id="offlineAppsListLabel">&offlineAppsList.label;</label>
+                <listbox id="offlineAppsList"
+                         style="height: &offlineAppsList.height;;"
+                         flex="1"
+                         aria-labelledby="offlineAppsListLabel"
+                         onselect="gAdvancedPane.offlineAppSelected(event);">
+                </listbox>
+              </vbox>
+              <vbox pack="end">
+                <button id="offlineAppsListRemove"
+                        disabled="true"
+                        label="&offlineAppsListRemove.label;"
+                        accesskey="&offlineAppsListRemove.accesskey;" 
+                        oncommand="gAdvancedPane.removeOfflineApp();"/>
+              </vbox>
+            </hbox>
+          </groupbox>
         </tabpanel>
 
         <!-- Update -->
diff --git a/netwerk/cache/nsCacheService.cpp b/netwerk/cache/nsCacheService.cpp
index d0c6f5ba4ea7..83e785e08abd 100644
--- a/netwerk/cache/nsCacheService.cpp
+++ b/netwerk/cache/nsCacheService.cpp
@@ -84,6 +84,8 @@
 
 #define DISK_CACHE_ENABLE_PREF      "browser.cache.disk.enable"
 #define DISK_CACHE_DIR_PREF         "browser.cache.disk.parent_directory"
+#define DISK_CACHE_SMART_SIZE_FIRST_RUN_PREF "browser.cache.disk.smart_size.first_run"
+#define DISK_CACHE_SMART_SIZE_ENABLED_PREF  "browser.cache.disk.smart_size.enabled"
 #define DISK_CACHE_CAPACITY_PREF    "browser.cache.disk.capacity"
 #define DISK_CACHE_MAX_ENTRY_SIZE_PREF "browser.cache.disk.max_entry_size"
 #define DISK_CACHE_CAPACITY         256000
@@ -106,6 +108,7 @@ static const char * observerList[] = {
 static const char * prefList[] = { 
 #ifdef NECKO_DISK_CACHE
     DISK_CACHE_ENABLE_PREF,
+    DISK_CACHE_SMART_SIZE_ENABLED_PREF,
     DISK_CACHE_CAPACITY_PREF,
     DISK_CACHE_DIR_PREF,
 #endif
@@ -153,6 +156,10 @@ public:
     PRBool          MemoryCacheEnabled();
     PRInt32         MemoryCacheCapacity();
 
+private:
+    bool                    PermittedToSmartSize(nsIPrefBranch*, PRBool firstRun);
+    PRUint32                GetSmartCacheSize(void);
+
 private:
     PRBool                  mHaveProfile;
     
@@ -302,6 +309,27 @@ nsCacheProfilePrefObserver::Observe(nsISupports *     subject,
             if (NS_FAILED(rv))  return rv;
             mDiskCacheCapacity = PR_MAX(0, capacity);
             nsCacheService::SetDiskCacheCapacity(mDiskCacheCapacity);
+       
+        // Update the cache capacity when smart sizing is turned on/off 
+        } else if (!strcmp(DISK_CACHE_SMART_SIZE_ENABLED_PREF, data.get())) {
+            // Is the update because smartsizing was turned on, or off?
+            PRBool smartSizeEnabled;
+            rv = branch->GetBoolPref(DISK_CACHE_SMART_SIZE_ENABLED_PREF,
+                                     &smartSizeEnabled);
+            if (NS_FAILED(rv)) return rv;
+            PRInt32 newCapacity = 0;
+            if (smartSizeEnabled) {
+              // Smart sizing switched on: recalculate the capacity.
+              newCapacity = GetSmartCacheSize() / 1024;
+            } else {
+              // Smart sizing switched off: use user specified size
+              rv = branch->GetIntPref(DISK_CACHE_CAPACITY_PREF, &newCapacity);
+              if (NS_FAILED(rv)) return rv;
+            } 
+            
+            mDiskCacheCapacity = PR_MAX(0, newCapacity);
+            nsCacheService::SetDiskCacheCapacity(mDiskCacheCapacity);
+               
 #if 0            
         } else if (!strcmp(DISK_CACHE_DIR_PREF, data.get())) {
             // XXX We probaby don't want to respond to this pref except after
@@ -399,6 +427,104 @@ nsCacheProfilePrefObserver::Observe(nsISupports *     subject,
 }
 
 
+ /* Computes our best guess for the default size of the user's disk cache, 
+  * based on the amount of space they have free on their hard drive. 
+  * We use a tiered scheme: the more space available, 
+  * the larger the disk cache will be. However, we do not want
+  * to enable the disk cache to grow to an unbounded size, so the larger the
+  * user's available space is, the smaller of a percentage we take. We set a
+  * lower bound of 50MB and an upper bound of 1GB.  
+  *
+  *@param:  None.
+  *@return: The size that the user's disk cache should default to, in bytes.
+  */
+PRUint32
+nsCacheProfilePrefObserver::GetSmartCacheSize(void) {
+  // Let our base line be 250MB. 
+  const PRInt32 BASE_LINE = 250 * 1024 * 1024;
+  const PRInt32 MIN_SIZE = 50 * 1024 * 1024;
+  const PRInt32 MAX_SIZE = 1024 * 1024 * 1024;
+  // Get a handle to disk where cache lives, so we can check for free space
+  nsresult rv;
+  nsCOMPtr<nsIFile> profileDirectory;
+  rv = NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
+                              getter_AddRefs(profileDirectory));
+  if (NS_FAILED(rv)) { 
+    return BASE_LINE;
+  }
+  nsCOMPtr<nsILocalFile> diskHandle = do_QueryInterface(profileDirectory);
+  PRInt64 bytesAvailable;
+  diskHandle->GetDiskSpaceAvailable(&bytesAvailable);
+  
+  /* 0MB <= Available < 500MB
+   * Use between 50MB  and 200MB
+   */ 
+  if (bytesAvailable < BASE_LINE * 2) {
+    return PR_MAX(MIN_SIZE, bytesAvailable * 4 / 10);
+  }
+  
+  /* 500MB <= Available < 2500MB
+   * Use 250MB 
+   */
+  if (bytesAvailable < static_cast<PRInt64>(BASE_LINE) * 10) {
+    return BASE_LINE;
+  }
+
+  /* 2500MB <= Available < 5000MB 
+   * Use between 250MB and 500MB
+   */
+  if (bytesAvailable < static_cast<PRInt64>(BASE_LINE) * 20) {
+    return bytesAvailable / 10;
+  }
+
+  /* 5000MB <= Available < 50000MB 
+   * Use 625MB
+   */
+  if (bytesAvailable < static_cast<PRInt64>(BASE_LINE) * 200 ) {
+    return BASE_LINE * 5 / 2;
+  }
+
+  /* 50000MB <= Available < 75000MB
+   * Use 800MB
+   */
+  if (bytesAvailable < static_cast<PRInt64>(BASE_LINE) * 300) {
+    return BASE_LINE / 5 * 16;  
+  }
+  
+  /* We have come within range of the ceiling
+   * Use 1GB
+   */
+  return MAX_SIZE;
+}
+
+/* Determine if we are permitted to dynamically size the user's disk cache based
+ * on their disk space available. We may do this so long as the pref 
+ * smart_size.enabled is true.
+ */
+bool
+nsCacheProfilePrefObserver::PermittedToSmartSize(nsIPrefBranch* branch, PRBool
+                                                 firstRun)
+{
+  nsresult rv;
+  // If user has explicitly set cache size, do not use smart-sizing by default.
+  if (firstRun) {
+    // check if user has set cache size in the past
+    PRBool userSet;
+    rv = branch->PrefHasUserValue(DISK_CACHE_CAPACITY_PREF, &userSet);
+    if (NS_FAILED(rv)) userSet = PR_TRUE;
+    if (userSet) {
+      branch->SetBoolPref(DISK_CACHE_SMART_SIZE_ENABLED_PREF, PR_FALSE);
+      return false;
+    }
+  }
+  PRBool smartSizeEnabled; 
+  rv = branch->GetBoolPref(DISK_CACHE_SMART_SIZE_ENABLED_PREF,
+                           &smartSizeEnabled);
+  if (NS_FAILED(rv)) return false;
+  return !!smartSizeEnabled;
+}
+
+
 nsresult
 nsCacheProfilePrefObserver::ReadPrefs(nsIPrefBranch* branch)
 {
@@ -456,6 +582,27 @@ nsCacheProfilePrefObserver::ReadPrefs(nsIPrefBranch* branch)
         if (directory)
             mDiskCacheParentDirectory = do_QueryInterface(directory, &rv);
     }
+    if (mDiskCacheParentDirectory) {
+      PRBool firstSmartSizeRun;
+      rv = branch->GetBoolPref(DISK_CACHE_SMART_SIZE_FIRST_RUN_PREF, &firstSmartSizeRun); 
+      if (NS_FAILED(rv)) firstSmartSizeRun = PR_FALSE;
+      if (PermittedToSmartSize(branch, firstSmartSizeRun)) {
+        // This change will be reflected in UI and about:cache
+        mDiskCacheCapacity = nsCacheProfilePrefObserver::GetSmartCacheSize() /
+                             1024; // convert to KB.
+        if (firstSmartSizeRun) {
+          // It is no longer our first run
+          rv = branch->SetBoolPref(DISK_CACHE_SMART_SIZE_FIRST_RUN_PREF, PR_FALSE);
+          if (NS_FAILED(rv)) 
+            NS_WARNING("Failed setting first_run pref in ReadPrefs.");
+        
+          // As a starting point, set disk.capacity to equal smart size
+          rv = branch->SetIntPref(DISK_CACHE_CAPACITY_PREF, mDiskCacheCapacity);
+          if (NS_FAILED(rv)) 
+            NS_WARNING("Failed setting disk.capacity pref in ReadPrefs.");
+        }
+      }
+    }
 #endif // !NECKO_DISK_CACHE
 
 #ifdef NECKO_OFFLINE_CACHE