Bug 316732 - Allow for hashing on nsIFile by introducing a new nsIHashable interface and implementing it for the file types r=darin

xpcom/ds/Makefile.in

@@ -122,6 +122,7 @@ XPIDLSRCS	= \
 		nsIAtomService.idl \
 		nsICollection.idl \
 		nsIEnumerator.idl \
+		nsIHashable.idl \
 		nsIINIParser.idl \
 		nsIPersistentProperties2.idl \
 		nsIProperty.idl \

xpcom/ds/nsIHashable.idl

@@ -0,0 +1,58 @@
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Mozilla XPCOM.
+ *
+ * The Initial Developer of the Original Code is
+ * Benjamin Smedberg <benjamin@smedbergs.us>.
+ *
+ * Portions created by the Initial Developer are Copyright (C) 2005
+ * the Mozilla Foundation <http://www.mozilla.org/>. All Rights Reserved.
+ *
+ * Contributor(s):
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#include "nsISupports.idl"
+
+/**
+ * Represents an object that can be stored in a hashtable.
+ */
+
+[scriptable, uuid(17e595fa-b57a-4933-bd0f-b1812e8ab188)]
+interface nsIHashable : nsISupports
+{
+  /**
+   * Is this object the equivalent of the other object?
+   */
+  boolean equals(in nsIHashable aOther);
+
+  /**
+   * A generated hashcode for this object. Objects that are equivalent
+   * must have the same hash code. Getting this property should never
+   * throw an exception!
+   */
+  readonly attribute unsigned long hashCode;
+};

xpcom/glue/nsHashKeys.h

@@ -40,6 +40,7 @@
 
 #include "nsID.h"
 #include "nsISupports.h"
+#include "nsIHashable.h"
 #include "nsCOMPtr.h"
 #include "pldhash.h"
 #include NEW_H
@@ -317,4 +318,44 @@ private:
   const char* mKey;
 };
 
+/**
+ * Hashtable key class to use with objects that support nsIHashable
+ */
+class nsHashableHashKey : public PLDHashEntryHdr
+{
+public:
+    typedef nsIHashable* KeyType;
+    typedef const nsIHashable* KeyTypePointer;
+
+    nsHashableHashKey(const nsIHashable* aKey) :
+        mKey(NS_CONST_CAST(nsIHashable*, aKey)) { }
+    nsHashableHashKey(const nsHashableHashKey& toCopy) :
+        mKey(toCopy.mKey) { }
+    ~nsHashableHashKey() { }
+
+    nsIHashable* GetKey() const { return mKey; }
+    const nsIHashable* GetKeyPointer() const { return mKey; }
+
+    PRBool KeyEquals(const nsIHashable* aKey) const {
+        PRBool eq;
+        if (NS_SUCCEEDED(mKey->Equals(NS_CONST_CAST(nsIHashable*,aKey), &eq))) {
+            return eq;
+        }
+        return PR_FALSE;
+    }
+
+    static const nsIHashable* KeyToPointer(nsIHashable* aKey) { return aKey; }
+    static PLDHashNumber HashKey(const nsIHashable* aKey) {
+        PRUint32 code = 8888; // magic number if GetHashCode fails :-(
+        nsresult rv = NS_CONST_CAST(nsIHashable*,aKey)->GetHashCode(&code);
+        NS_ASSERTION(NS_SUCCEEDED(rv), "GetHashCode should not throw!");
+        return code;
+    }
+    
+    enum { ALLOW_MEMMOVE = PR_TRUE };
+
+private:
+    nsCOMPtr<nsIHashable> mKey;
+};
+
 #endif // nsTHashKeys_h__

xpcom/io/nsLocalFileOSX.cpp

@@ -2038,6 +2038,28 @@ nsresult nsLocalFile::CFStringReftoUTF8(CFStringRef aInStrRef, nsACString& aOutS
   return rv;
 }
 
+// nsIHashable
+
+NS_IMETHODIMP
+nsLocalFile::Equals(nsIHashable* aOther, PRBool *aResult)
+{
+    nsCOMPtr<nsIFile> otherfile(do_QueryInterface(aOther));
+    if (!otherfile) {
+        *aResult = PR_FALSE;
+        return NS_OK;
+    }
+
+    return Equals(otherfile, aResult);
+}
+
+NS_IMETHODIMP
+nsLocalFile::GetHashCode(PRUint32 *aResult)
+{
+    CFURLRef whichURLRef = mFollowLinks ? mTargetRef : mBaseRef;
+    *aResult = CFHash(whichURLRef);
+    return NS_OK;
+}
+
 //*****************************************************************************
 //  Global Functions
 //*****************************************************************************

xpcom/io/nsLocalFileOSX.h

@@ -41,6 +41,7 @@
 
 #include "nsILocalFileMac.h"
 #include "nsString.h"
+#include "nsIHashable.h"
 
 class nsDirEnumerator;
 
@@ -55,7 +56,8 @@ class nsDirEnumerator;
 // for the conversion to NFC (composed Unicode) done in "non-Native" getters.
 //*****************************************************************************
 
-class NS_COM nsLocalFile : public nsILocalFileMac
+class NS_COM nsLocalFile : public nsILocalFileMac,
+                           public nsIHashable
 {
     friend class nsDirEnumerator;
     
@@ -70,6 +72,7 @@ public:
     NS_DECL_NSIFILE
     NS_DECL_NSILOCALFILE
     NS_DECL_NSILOCALFILEMAC
+    NS_DECL_NSIHASHABLE
 
 public:
 

xpcom/io/nsLocalFileUnix.cpp

@@ -1750,6 +1750,28 @@ nsLocalFile::GetTarget(nsAString &_retval)
 {   
     GET_UCS(GetNativeTarget, _retval);
 }
+
+// nsIHashable
+
+NS_IMETHODIMP
+nsLocalFile::Equals(nsIHashable* aOther, PRBool *aResult)
+{
+    nsCOMPtr<nsIFile> otherFile(do_QueryInterface(aOther));
+    if (!otherFile) {
+        *aResult = PR_FALSE;
+        return NS_OK;
+    }
+
+    return Equals(otherFile, aResult);
+}
+
+NS_IMETHODIMP
+nsLocalFile::GetHashCode(PRUint32 *aResult)
+{
+    *aResult = nsCRT::HashCode(mPath.get());
+    return NS_OK;
+}
+
 nsresult 
 NS_NewLocalFile(const nsAString &path, PRBool followLinks, nsILocalFile* *result)
 {

xpcom/io/nsLocalFileUnix.h

@@ -51,6 +51,7 @@
 #include "nscore.h"
 #include "nsString.h"
 #include "nsReadableUtils.h"
+#include "nsIHashable.h"
 
 /** 
  *  we need these for statfs()
@@ -80,7 +81,8 @@
     #include <sys/mount.h>
 #endif
 
-class NS_COM nsLocalFile : public nsILocalFile
+class NS_COM nsLocalFile : public nsILocalFile,
+                           public nsIHashable
 {
 public:
     NS_DEFINE_STATIC_CID_ACCESSOR(NS_LOCAL_FILE_CID)
@@ -98,6 +100,9 @@ public:
     // nsILocalFile
     NS_DECL_NSILOCALFILE
 
+    // nsIHashable
+    NS_DECL_NSIHASHABLE
+
 public:
     static void GlobalInit();
     static void GlobalShutdown();

xpcom/io/nsLocalFileWin.cpp

@@ -2524,6 +2524,37 @@ nsLocalFile::GetTarget(nsAString &_retval)
     return rv;
 }
 
+// nsIHashable
+
+NS_IMETHODIMP
+nsLocalFile::Equals(nsIHashable* aOther, PRBool *aResult)
+{
+    nsCOMPtr<nsIFile> otherfile(do_QueryInterface(aOther));
+    if (!otherfile) {
+        *aResult = PR_FALSE;
+        return NS_OK;
+    }
+
+    return Equals(otherfile, aResult);
+}
+
+NS_IMETHODIMP
+nsLocalFile::GetHashCode(PRUint32 *aResult)
+{
+    // In order for short and long path names to hash to the same value we
+    // always hash on the short pathname.
+
+    char thisshort[MAX_PATH];
+    DWORD thisr = GetShortPathName(mWorkingPath.get(),
+                                   thisshort, sizeof(thisshort));
+    if (thisr < sizeof(thisshort))
+        *aResult = nsCRT::HashCode(thisshort);
+    else
+        *aResult = nsCRT::HashCode(mWorkingPath.get());
+
+    return NS_OK;
+}
+
 nsresult
 NS_NewLocalFile(const nsAString &path, PRBool followLinks, nsILocalFile* *result)
 {

xpcom/io/nsLocalFileWin.h

@@ -48,6 +48,7 @@
 #include "nsIFile.h"
 #include "nsIFactory.h"
 #include "nsILocalFileWin.h"
+#include "nsIHashable.h"
 
 #include "windows.h"
 
@@ -61,7 +62,8 @@ DEFINE_OLEGUID(IID_IPersistFile, 0x0000010BL, 0, 0);
 
 #include <sys/stat.h>
 
-class nsLocalFile : public nsILocalFileWin
+class nsLocalFile : public nsILocalFileWin,
+                    public nsIHashable
 {
 public:
     NS_DEFINE_STATIC_CID_ACCESSOR(NS_LOCAL_FILE_CID)
@@ -82,6 +84,9 @@ public:
     // nsILocalFileWin interface
     NS_DECL_NSILOCALFILEWIN
 
+    // nsIHashable interface
+    NS_DECL_NSIHASHABLE
+
 public:
     static void GlobalInit();
     static void GlobalShutdown();