From 7982ac318d89e218399f52c3855b2f3a11f237ee Mon Sep 17 00:00:00 2001
From: Joe Drew <joe@drew.ca>
Date: Thu, 30 Jun 2011 21:58:28 -0400
Subject: [PATCH] Bug 552605 - Change "must validate if expired" to "must
 always validate" in the image cache, to fit with the spirit of the HTTP spec.
 r=jrmuizel f=bz

---
 modules/libpr0n/src/imgLoader.cpp  | 11 +++++++----
 modules/libpr0n/src/imgLoader.h    | 10 +++++-----
 modules/libpr0n/src/imgRequest.cpp |  9 ++-------
 3 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/modules/libpr0n/src/imgLoader.cpp b/modules/libpr0n/src/imgLoader.cpp
index fb875c28544..cba7c5fe2a3 100644
--- a/modules/libpr0n/src/imgLoader.cpp
+++ b/modules/libpr0n/src/imgLoader.cpp
@@ -401,7 +401,7 @@ static PRBool NewRequestAndEntry(nsIURI *uri, imgRequest **request, imgCacheEntr
   if (!*request)
     return PR_FALSE;
 
-  *entry = new imgCacheEntry(*request, /* mustValidateIfExpired = */ isFile);
+  *entry = new imgCacheEntry(*request, /* mustValidate = */ isFile);
   if (!*entry) {
     delete *request;
     return PR_FALSE;
@@ -425,6 +425,9 @@ static PRBool ShouldRevalidateEntry(imgCacheEntry *aEntry,
   if (aFlags & nsIRequest::VALIDATE_ALWAYS) {
     bValidateEntry = PR_TRUE;
   }
+  else if (aEntry->GetMustValidate()) {
+    bValidateEntry = PR_TRUE;
+  }
   //
   // The cache entry has expired...  Determine whether the stale cache
   // entry can be used without validation...
@@ -438,7 +441,7 @@ static PRBool ShouldRevalidateEntry(imgCacheEntry *aEntry,
     if (aFlags & (nsIRequest::VALIDATE_NEVER | 
                   nsIRequest::VALIDATE_ONCE_PER_SESSION)) 
     {
-      bValidateEntry = aEntry->GetMustValidateIfExpired();
+      bValidateEntry = PR_FALSE;
     }
     //
     // LOAD_FROM_CACHE allows a stale cache entry to be used... Otherwise,
@@ -526,12 +529,12 @@ static PRUint32 SecondsFromPRTime(PRTime prTime)
   return PRUint32(PRInt64(prTime) / PRInt64(PR_USEC_PER_SEC));
 }
 
-imgCacheEntry::imgCacheEntry(imgRequest *request, PRBool mustValidateIfExpired /* = PR_FALSE */)
+imgCacheEntry::imgCacheEntry(imgRequest *request, PRBool mustValidate /* = PR_FALSE */)
  : mRequest(request),
    mDataSize(0),
    mTouchedTime(SecondsFromPRTime(PR_Now())),
    mExpiryTime(0),
-   mMustValidateIfExpired(mustValidateIfExpired),
+   mMustValidate(mustValidate),
    mEvicted(PR_FALSE),
    mHasNoProxies(PR_TRUE)
 {}
diff --git a/modules/libpr0n/src/imgLoader.h b/modules/libpr0n/src/imgLoader.h
index 16d2bbcb982..bfa20b0e253 100644
--- a/modules/libpr0n/src/imgLoader.h
+++ b/modules/libpr0n/src/imgLoader.h
@@ -123,13 +123,13 @@ public:
     Touch();
   }
 
-  PRBool GetMustValidateIfExpired() const
+  PRBool GetMustValidate() const
   {
-    return mMustValidateIfExpired;
+    return mMustValidate;
   }
-  void SetMustValidateIfExpired(PRBool aValidate)
+  void SetMustValidate(PRBool aValidate)
   {
-    mMustValidateIfExpired = aValidate;
+    mMustValidate = aValidate;
     Touch();
   }
 
@@ -178,7 +178,7 @@ private: // data
   PRInt32 mTouchedTime;
   PRInt32 mExpiryTime;
   nsExpirationState mExpirationState;
-  PRPackedBool mMustValidateIfExpired : 1;
+  PRPackedBool mMustValidate : 1;
   PRPackedBool mEvicted : 1;
   PRPackedBool mHasNoProxies : 1;
 };
diff --git a/modules/libpr0n/src/imgRequest.cpp b/modules/libpr0n/src/imgRequest.cpp
index a8a63b3d15f..6453d2506b9 100644
--- a/modules/libpr0n/src/imgRequest.cpp
+++ b/modules/libpr0n/src/imgRequest.cpp
@@ -530,13 +530,8 @@ void imgRequest::SetCacheValidation(imgCacheEntry* aCacheEntry, nsIRequest* aReq
       }
     }
 
-    //
-    // Determine whether the cache entry must be revalidated when it expires.
-    // If so, then the cache entry must *not* be used during HISTORY loads if
-    // it has expired.
-    //
+    // Determine whether the cache entry must be revalidated when we try to use it.
     // Currently, only HTTP specifies this information...
-    //
     nsCOMPtr<nsIHttpChannel> httpChannel(do_QueryInterface(aRequest));
     if (httpChannel) {
       PRBool bMustRevalidate = PR_FALSE;
@@ -561,7 +556,7 @@ void imgRequest::SetCacheValidation(imgCacheEntry* aCacheEntry, nsIRequest* aReq
       // multiple calls to this function don't override an earlier decision to
       // validate by making validation a one-way decision.
       if (bMustRevalidate)
-        aCacheEntry->SetMustValidateIfExpired(bMustRevalidate);
+        aCacheEntry->SetMustValidate(bMustRevalidate);
     }
   }
 }