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      1 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "chrome/browser/cocoa/file_metadata.h"
      6 
      7 #include <ApplicationServices/ApplicationServices.h>
      8 #include <Foundation/Foundation.h>
      9 
     10 #include "base/file_path.h"
     11 #include "base/logging.h"
     12 #include "base/mac/mac_util.h"
     13 #include "base/mac/scoped_cftyperef.h"
     14 #include "googleurl/src/gurl.h"
     15 
     16 namespace file_metadata {
     17 
     18 // As of Mac OS X 10.4 ("Tiger"), files can be tagged with metadata describing
     19 // various attributes.  Metadata is integrated with the system's Spotlight
     20 // feature and is searchable.  Ordinarily, metadata can only be set by
     21 // Spotlight importers, which requires that the importer own the target file.
     22 // However, there's an attribute intended to describe the origin of a
     23 // file, that can store the source URL and referrer of a downloaded file.
     24 // It's stored as a "com.apple.metadata:kMDItemWhereFroms" extended attribute,
     25 // structured as a binary1-format plist containing a list of sources.  This
     26 // attribute can only be populated by the downloader, not a Spotlight importer.
     27 // Safari on 10.4 and later populates this attribute.
     28 //
     29 // With this metadata set, you can locate downloads by performing a Spotlight
     30 // search for their source or referrer URLs, either from within the Spotlight
     31 // UI or from the command line:
     32 //     mdfind 'kMDItemWhereFroms == "http://releases.mozilla.org/*"'
     33 //
     34 // There is no documented API to set metadata on a file directly as of the
     35 // 10.5 SDK.  The MDSetItemAttribute function does exist to perform this task,
     36 // but it's undocumented.
     37 void AddOriginMetadataToFile(const FilePath& file, const GURL& source,
     38                              const GURL& referrer) {
     39   // There's no declaration for MDItemSetAttribute in any known public SDK.
     40   // It exists in the 10.4 and 10.5 runtimes.  To play it safe, do the lookup
     41   // at runtime instead of declaring it ourselves and linking against what's
     42   // provided.  This has two benefits:
     43   //  - If Apple relents and declares the function in a future SDK (it's
     44   //    happened before), our build won't break.
     45   //  - If Apple removes or renames the function in a future runtime, the
     46   //    loader won't refuse to let the application launch.  Instead, we'll
     47   //    silently fail to set any metadata.
     48   typedef OSStatus (*MDItemSetAttribute_type)(MDItemRef, CFStringRef,
     49                                               CFTypeRef);
     50   static MDItemSetAttribute_type md_item_set_attribute_func = NULL;
     51 
     52   static bool did_symbol_lookup = false;
     53   if (!did_symbol_lookup) {
     54     did_symbol_lookup = true;
     55     CFBundleRef metadata_bundle =
     56         CFBundleGetBundleWithIdentifier(CFSTR("com.apple.Metadata"));
     57     if (!metadata_bundle)
     58       return;
     59 
     60     md_item_set_attribute_func = (MDItemSetAttribute_type)
     61         CFBundleGetFunctionPointerForName(metadata_bundle,
     62                                           CFSTR("MDItemSetAttribute"));
     63   }
     64   if (!md_item_set_attribute_func)
     65     return;
     66 
     67   NSString* file_path =
     68       [NSString stringWithUTF8String:file.value().c_str()];
     69   if (!file_path)
     70     return;
     71 
     72   base::mac::ScopedCFTypeRef<MDItemRef> md_item(
     73       MDItemCreate(NULL, base::mac::NSToCFCast(file_path)));
     74   if (!md_item)
     75     return;
     76 
     77   // We won't put any more than 2 items into the attribute.
     78   NSMutableArray* list = [NSMutableArray arrayWithCapacity:2];
     79 
     80   // Follow Safari's lead: the first item in the list is the source URL of
     81   // the downloaded file. If the referrer is known, store that, too.
     82   NSString* origin_url = [NSString stringWithUTF8String:source.spec().c_str()];
     83   if (origin_url)
     84     [list addObject:origin_url];
     85   NSString* referrer_url =
     86       [NSString stringWithUTF8String:referrer.spec().c_str()];
     87   if (referrer_url)
     88     [list addObject:referrer_url];
     89 
     90   md_item_set_attribute_func(md_item, kMDItemWhereFroms,
     91                              base::mac::NSToCFCast(list));
     92 }
     93 
     94 // The OS will automatically quarantine files due to the
     95 // LSFileQuarantineEnabled entry in our Info.plist, but it knows relatively
     96 // little about the files. We add more information about the download to
     97 // improve the UI shown by the OS when the users tries to open the file.
     98 void AddQuarantineMetadataToFile(const FilePath& file, const GURL& source,
     99                                  const GURL& referrer) {
    100   FSRef file_ref;
    101   if (!base::mac::FSRefFromPath(file.value(), &file_ref))
    102     return;
    103 
    104   NSMutableDictionary* quarantine_properties = nil;
    105   CFTypeRef quarantine_properties_base = NULL;
    106   if (LSCopyItemAttribute(&file_ref, kLSRolesAll, kLSItemQuarantineProperties,
    107                             &quarantine_properties_base) == noErr) {
    108     if (CFGetTypeID(quarantine_properties_base) ==
    109         CFDictionaryGetTypeID()) {
    110       // Quarantine properties will already exist if LSFileQuarantineEnabled
    111       // is on and the file doesn't match an exclusion.
    112       quarantine_properties =
    113           [[(NSDictionary*)quarantine_properties_base mutableCopy] autorelease];
    114     } else {
    115       LOG(WARNING) << "kLSItemQuarantineProperties is not a dictionary on file "
    116                    << file.value();
    117     }
    118     CFRelease(quarantine_properties_base);
    119   }
    120 
    121   if (!quarantine_properties) {
    122     // If there are no quarantine properties, then the file isn't quarantined
    123     // (e.g., because the user has set up exclusions for certain file types).
    124     // We don't want to add any metadata, because that will cause the file to
    125     // be quarantined against the user's wishes.
    126     return;
    127   }
    128 
    129   // kLSQuarantineAgentNameKey, kLSQuarantineAgentBundleIdentifierKey, and
    130   // kLSQuarantineTimeStampKey are set for us (see LSQuarantine.h), so we only
    131   // need to set the values that the OS can't infer.
    132 
    133   if (![quarantine_properties valueForKey:(NSString*)kLSQuarantineTypeKey]) {
    134     CFStringRef type = (source.SchemeIs("http") || source.SchemeIs("https"))
    135                        ? kLSQuarantineTypeWebDownload
    136                        : kLSQuarantineTypeOtherDownload;
    137     [quarantine_properties setValue:(NSString*)type
    138                              forKey:(NSString*)kLSQuarantineTypeKey];
    139   }
    140 
    141   if (![quarantine_properties
    142           valueForKey:(NSString*)kLSQuarantineOriginURLKey] &&
    143       referrer.is_valid()) {
    144     NSString* referrer_url =
    145         [NSString stringWithUTF8String:referrer.spec().c_str()];
    146     [quarantine_properties setValue:referrer_url
    147                              forKey:(NSString*)kLSQuarantineOriginURLKey];
    148   }
    149 
    150   if (![quarantine_properties valueForKey:(NSString*)kLSQuarantineDataURLKey] &&
    151       source.is_valid()) {
    152     NSString* origin_url =
    153         [NSString stringWithUTF8String:source.spec().c_str()];
    154     [quarantine_properties setValue:origin_url
    155                              forKey:(NSString*)kLSQuarantineDataURLKey];
    156   }
    157 
    158   OSStatus os_error = LSSetItemAttribute(&file_ref, kLSRolesAll,
    159                                          kLSItemQuarantineProperties,
    160                                          quarantine_properties);
    161   if (os_error != noErr) {
    162     LOG(WARNING) << "Unable to set quarantine attributes on file "
    163                  << file.value();
    164   }
    165 }
    166 
    167 }  // namespace file_metadata
    168