xpcom/io/nsIFile.idl
author Henri Sivonen <hsivonen@hsivonen.fi>
Fri, 06 Jul 2018 10:44:43 +0300
changeset 489140 4ef0f163fdeb9afeddd87b37bfd987298c038542
parent 475773 8b49c4e339aeec0eb6ec4ad238dbd43adf958062
child 491438 d40ab2ee60232d20ee38d3601ef15a85fa8c6d86
permissions -rw-r--r--
Bug 1402247 - Use encoding_rs for XPCOM string encoding conversions. r=Nika,erahm,froydnj. Correctness improvements: * UTF errors are handled safely per spec instead of dangerously truncating strings. * There are fewer converter implementations. Performance improvements: * The old code did exact buffer length math, which meant doing UTF math twice on each input string (once for length calculation and another time for conversion). Exact length math is more complicated when handling errors properly, which the old code didn't do. The new code does UTF math on the string content only once (when converting) but risks allocating more than once. There are heuristics in place to lower the probability of reallocation in cases where the double math avoidance isn't enough of a saving to absorb an allocation and memcpy. * Previously, in UTF-16 <-> UTF-8 conversions, an ASCII prefix was optimized but a single non-ASCII code point pessimized the rest of the string. The new code tries to get back on the fast ASCII path. * UTF-16 to Latin1 conversion guarantees less about handling of out-of-range input to eliminate an operation from the inner loop on x86/x86_64. * When assigning to a pre-existing string, the new code tries to reuse the old buffer instead of first releasing the old buffer and then allocating a new one. * When reallocating from the new code, the memcpy covers only the data that is part of the logical length of the old string instead of memcpying the whole capacity. (For old callers old excess memcpy behavior is preserved due to bogus callers. See bug 1472113.) * UTF-8 strings in XPConnect that are in the Latin1 range are passed to SpiderMonkey as Latin1. New features: * Conversion between UTF-8 and Latin1 is added in order to enable faster future interop between Rust code (or otherwise UTF-8-using code) and text node and SpiderMonkey code that uses Latin1. MozReview-Commit-ID: JaJuExfILM9

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsISupports.idl"
#include "nsIDirectoryEnumerator.idl"

%{C++
struct PRFileDesc;
struct PRLibrary;
#include <stdio.h>
#include "mozilla/Path.h"
#include "nsCOMPtr.h"
#include "nsStringFwd.h"
namespace mozilla {
using PathString = nsTString<filesystem::Path::value_type>;
using PathSubstring = nsTSubstring<filesystem::Path::value_type>;
} // namespace mozilla
%}

[ptr] native PRFileDescStar(PRFileDesc);
[ptr] native PRLibraryStar(PRLibrary);
[ptr] native FILE(FILE);
native PathString(mozilla::PathString);

/**
 * An nsIFile is an abstract representation of a filename. It manages
 * filename encoding issues, pathname component separators ('/' vs. '\\'
 * vs. ':') and weird stuff like differing volumes with identical names, as
 * on pre-Darwin Macintoshes.
 *
 * This file has long introduced itself to new hackers with this opening
 * paragraph:
 *
 *    This is the only correct cross-platform way to specify a file.
 *    Strings are not such a way. If you grew up on windows or unix, you
 *    may think they are.  Welcome to reality.
 *
 * While taking the pose struck here to heart would be uncalled for, one
 * may safely conclude that writing cross-platform code is an embittering
 * experience.
 *
 * All methods with string parameters have two forms.  The preferred
 * form operates on UCS-2 encoded characters strings.  An alternate
 * form operates on characters strings encoded in the "native" charset.
 *
 * A string containing characters encoded in the native charset cannot
 * be safely passed to javascript via xpconnect.  Therefore, the "native
 * methods" are not scriptable.
 */
[scriptable, main_process_scriptable_only, uuid(2fa6884a-ae65-412a-9d4c-ce6e34544ba1), builtinclass]
interface nsIFile : nsISupports
{
    /**
     *  Create Types
     *
     *  NORMAL_FILE_TYPE - A normal file.
     *  DIRECTORY_TYPE   - A directory/folder.
     */
    const unsigned long NORMAL_FILE_TYPE = 0;
    const unsigned long DIRECTORY_TYPE   = 1;

    /**
     *  append[Native]
     *
     *  This function is used for constructing a descendent of the
     *  current nsIFile.
     *
     *   @param node
     *       A string which is intended to be a child node of the nsIFile.
     *       For the |appendNative| method, the node must be in the native
     *       filesystem charset.
     */
    void append(in AString node);
    [noscript] void appendNative(in ACString node);

    /**
     *  Normalize the pathName (e.g. removing .. and . components on Unix).
     */
    void normalize();

    /**
     *  create
     *
     *  This function will create a new file or directory in the
     *  file system. Any nodes that have not been created or
     *  resolved, will be.  If the file or directory already
     *  exists create() will return NS_ERROR_FILE_ALREADY_EXISTS.
     *
     *   @param type
     *       This specifies the type of file system object
     *       to be made.  The only two types at this time
     *       are file and directory which are defined above.
     *       If the type is unrecongnized, we will return an
     *       error (NS_ERROR_FILE_UNKNOWN_TYPE).
     *
     *   @param permissions
     *       The unix style octal permissions.  This may
     *       be ignored on systems that do not need to do
     *       permissions.
     */
    [must_use] void create(in unsigned long type, in unsigned long permissions);

    /**
     *  Accessor to the leaf name of the file itself.      
     *  For the |nativeLeafName| method, the nativeLeafName must 
     *  be in the native filesystem charset.
     */
    attribute AString leafName;
    [noscript] attribute ACString nativeLeafName;

    /**
     *  copyTo[Native]
     *
     *  This will copy this file to the specified newParentDir.
     *  If a newName is specified, the file will be renamed.
     *  If 'this' is not created we will return an error
     *  (NS_ERROR_FILE_TARGET_DOES_NOT_EXIST).
     *
     *  copyTo may fail if the file already exists in the destination 
     *  directory.
     *
     *  copyTo will NOT resolve aliases/shortcuts during the copy.
     *
     *   @param newParentDir
     *       This param is the destination directory. If the
     *       newParentDir is null, copyTo() will use the parent
     *       directory of this file. If the newParentDir is not
     *       empty and is not a directory, an error will be
     *       returned (NS_ERROR_FILE_DESTINATION_NOT_DIR). For the 
     *       |CopyToNative| method, the newName must be in the 
     *       native filesystem charset.
     *
     *   @param newName
     *       This param allows you to specify a new name for
     *       the file to be copied. This param may be empty, in
     *       which case the current leaf name will be used.
     */
    void copyTo(in nsIFile newParentDir, in AString newName);
    [noscript] void CopyToNative(in nsIFile newParentDir, in ACString newName);

    /**
     *  copyToFollowingLinks[Native]
     *
     *  This function is identical to copyTo with the exception that,
     *  as the name implies, it follows symbolic links.  The XP_UNIX
     *  implementation always follow symbolic links when copying.  For 
     *  the |CopyToFollowingLinks| method, the newName must be in the 
     *  native filesystem charset.
     */
    void copyToFollowingLinks(in nsIFile newParentDir, in AString newName);
    [noscript] void copyToFollowingLinksNative(in nsIFile newParentDir, in ACString newName);

    /**
     *  moveTo[Native]
     *
     *  A method to move this file or directory to newParentDir.
     *  If a newName is specified, the file or directory will be renamed.
     *  If 'this' is not created we will return an error
     *  (NS_ERROR_FILE_TARGET_DOES_NOT_EXIST).
     *  If 'this' is a file, and the destination file already exists, moveTo
     *  will replace the old file.
     *  This object is updated to refer to the new file.
     *
     *  moveTo will NOT resolve aliases/shortcuts during the copy.
     *  moveTo will do the right thing and allow copies across volumes.
     *  moveTo will return an error (NS_ERROR_FILE_DIR_NOT_EMPTY) if 'this' is
     *  a directory and the destination directory is not empty.
     *  moveTo will return an error (NS_ERROR_FILE_ACCESS_DENIED) if 'this' is
     *  a directory and the destination directory is not writable.
     *
     *   @param newParentDir
     *       This param is the destination directory. If the
     *       newParentDir is empty, moveTo() will rename the file
     *       within its current directory. If the newParentDir is
     *       not empty and does not name a directory, an error will
     *       be returned (NS_ERROR_FILE_DESTINATION_NOT_DIR).  For 
     *       the |moveToNative| method, the newName must be in the 
     *       native filesystem charset.
     *
     *   @param newName
     *       This param allows you to specify a new name for
     *       the file to be moved. This param may be empty, in
     *       which case the current leaf name will be used.
     */
    void moveTo(in nsIFile newParentDir, in AString newName);
    [noscript] void moveToNative(in nsIFile newParentDir, in ACString newName);

    /**
     *  renameTo
     *
     *  This method is identical to moveTo except that if this file or directory
     *  is moved to a a different volume, it fails and returns an error
     *  (NS_ERROR_FILE_ACCESS_DENIED).
     *  This object will still point to the old location after renaming.
     */
    void renameTo(in nsIFile newParentDir, in AString newName);
    [noscript] void renameToNative(in nsIFile newParentDir, in ACString newName);

    /**
     *  This will try to delete this file.  The 'recursive' flag
     *  must be PR_TRUE to delete directories which are not empty.
     *
     *  This will not resolve any symlinks.
     */
    void remove(in boolean recursive);

    /**
     *  Attributes of nsIFile.
     */

    attribute unsigned long permissions;
    attribute unsigned long permissionsOfLink;

    /**
     *  File Times are to be in milliseconds from
     *  midnight (00:00:00), January 1, 1970 Greenwich Mean
     *  Time (GMT).
     */
    attribute PRTime lastModifiedTime;
    attribute PRTime lastModifiedTimeOfLink;

    /**
     *  WARNING!  On the Mac, getting/setting the file size with nsIFile
     *  only deals with the size of the data fork.  If you need to
     *  know the size of the combined data and resource forks use the
     *  GetFileSizeWithResFork() method defined on nsILocalFileMac.
     */
    attribute int64_t fileSize;
    readonly attribute int64_t fileSizeOfLink;

    /**
     *  target & path
     *
     *  Accessor to the string path.  The native version of these
     *  strings are not guaranteed to be a usable path to pass to
     *  NSPR or the C stdlib.  There are problems that affect
     *  platforms on which a path does not fully specify a file
     *  because two volumes can have the same name (e.g., mac).
     *  This is solved by holding "private", native data in the
     *  nsIFile implementation.  This native data is lost when
     *  you convert to a string.
     *
     *      DO NOT PASS TO USE WITH NSPR OR STDLIB!
     *
     *  target
     *      Find out what the symlink points at.  Will give error
     *      (NS_ERROR_FILE_INVALID_PATH) if not a symlink.
     *
     *  path
     *      Find out what the nsIFile points at.
     *
     *  Note that the ACString attributes are returned in the 
     *  native filesystem charset.
     *
     */
    readonly attribute AString target;
    [noscript] readonly attribute ACString nativeTarget;
    readonly attribute AString path;
    [notxpcom,nostdcall,must_use] PathString nativePath();
%{C++
#ifndef XP_WIN
    nsresult GetNativePath(nsACString& aPath);
#endif
    /*
     * Returns a human-readable path string.
     */
    nsCString HumanReadablePath();
%}

    boolean exists();
    boolean isWritable();
    boolean isReadable();
    boolean isExecutable();
    boolean isHidden();
    boolean isDirectory();
    boolean isFile();
    boolean isSymlink();
    /**
     * Not a regular file, not a directory, not a symlink.
     */
    boolean isSpecial();

    /**
     *  createUnique
     *  
     *  This function will create a new file or directory in the
     *  file system. Any nodes that have not been created or
     *  resolved, will be.  If this file already exists, we try
     *  variations on the leaf name "suggestedName" until we find
     *  one that did not already exist.
     *
     *  If the search for nonexistent files takes too long
     *  (thousands of the variants already exist), we give up and
     *  return NS_ERROR_FILE_TOO_BIG.
     *
     *   @param type
     *       This specifies the type of file system object
     *       to be made.  The only two types at this time
     *       are file and directory which are defined above.
     *       If the type is unrecongnized, we will return an
     *       error (NS_ERROR_FILE_UNKNOWN_TYPE).
     *
     *   @param permissions
     *       The unix style octal permissions.  This may
     *       be ignored on systems that do not need to do
     *       permissions.
     */
    [must_use]
    void createUnique(in unsigned long type, in unsigned long permissions);

    /**
      * clone()
      *
      * This function will allocate and initialize a nsIFile object to the
      * exact location of the |this| nsIFile.
      *
      *   @param file
      *          A nsIFile which this object will be initialize
      *          with.
      *
      */
    nsIFile clone();

    /**
     *  Will determine if the inFile equals this.
     */
    boolean equals(in nsIFile inFile);

    /**
     *  Will determine if inFile is a descendant of this file.
     *  This routine looks in subdirectories too.
     */
    boolean contains(in nsIFile inFile);

    /**
     *  Parent will be null when this is at the top of the volume.
     */
    readonly attribute nsIFile parent;
    
    /**
     *  Returns an enumeration of the elements in a directory. Each
     *  element in the enumeration is an nsIFile.
     *
     *   @throws NS_ERROR_FILE_NOT_DIRECTORY if the current nsIFile does
     *           not specify a directory.
     */
    [binaryname(DirectoryEntriesImpl)]
    readonly attribute nsIDirectoryEnumerator directoryEntries;

    %{C++
    nsresult GetDirectoryEntries(nsISimpleEnumerator** aOut)
    {
      nsCOMPtr<nsIDirectoryEnumerator> dirEnum;
      nsresult rv = GetDirectoryEntries(getter_AddRefs(dirEnum));
      dirEnum.forget(aOut);
      return rv;
    };

    nsresult GetDirectoryEntries(nsIDirectoryEnumerator** aOut)
    {
      return GetDirectoryEntriesImpl(aOut);
    };
    %}

    /**
     *  initWith[Native]Path
     *
     *  This function will initialize the nsIFile object.  Any
     *  internal state information will be reset.
     *
     *   @param filePath       
     *       A string which specifies a full file path to a 
     *       location.  Relative paths will be treated as an
     *       error (NS_ERROR_FILE_UNRECOGNIZED_PATH).  For 
     *       initWithNativePath, the filePath must be in the native
     *       filesystem charset.
     */
    void initWithPath(in AString filePath);
    [noscript] void initWithNativePath(in ACString filePath);
    
    /**
     *  initWithFile
     *
     *  Initialize this object with another file
     *
     *   @param aFile
     *       the file this becomes equivalent to
     */
    void initWithFile(in nsIFile aFile);
    
    /**
     *  followLinks
     *
     *  This attribute will determine if the nsLocalFile will auto
     *  resolve symbolic links.  By default, this value will be false
     *  on all non unix systems.  On unix, this attribute is effectively
     *  a noop.  
     */
    attribute boolean followLinks;  

    /**
     * Flag for openNSPRFileDesc(), to hint to the OS that the file will be
     * read sequentially with agressive readahead.
     */
    const unsigned long OS_READAHEAD = 0x40000000;
    
    /**
     * Flag for openNSPRFileDesc(). Deprecated and unreliable!
     * Instead use NS_OpenAnonymousTemporaryFile() to create a temporary
     * file which will be deleted upon close!
     */
    const unsigned long DELETE_ON_CLOSE = 0x80000000;

    /**
     * Return the result of PR_Open on the file.  The caller is
     * responsible for calling PR_Close on the result.  On success, the
     * returned PRFileDescr must be non-null.
     *
     * @param flags the PR_Open flags from prio.h, plus optionally
     * OS_READAHEAD or DELETE_ON_CLOSE. OS_READAHEAD is a hint to the
     * OS that the file will be read sequentially with agressive
     * readahead. DELETE_ON_CLOSE is unreliable on Windows and is deprecated.
     * Instead use NS_OpenAnonymousTemporaryFile() to create a temporary
     * file which will be deleted upon close.
     */
    [noscript, must_use] PRFileDescStar openNSPRFileDesc(in long flags,
                                                         in long mode);

    /**
     * Return the result of fopen on the file.  The caller is
     * responsible for calling fclose on the result.  On success, the
     * returned FILE pointer must be non-null.
     */
    [noscript, must_use] FILE openANSIFileDesc(in string mode);

    /**
     * Return the result of PR_LoadLibrary on the file.  The caller is
     * responsible for calling PR_UnloadLibrary on the result.
     */
    [noscript, must_use] PRLibraryStar  load();

    // number of bytes available on disk to non-superuser
    [must_use] readonly attribute int64_t diskSpaceAvailable;

    /**
     *  appendRelative[Native]Path
     *
     *  Append a relative path to the current path of the nsIFile object.
     *
     *   @param relativeFilePath
     *       relativeFilePath is a native relative path. For security reasons,
     *       this cannot contain .. or cannot start with a directory separator.
     *       For the |appendRelativeNativePath| method, the relativeFilePath 
     *       must be in the native filesystem charset.
     */
    void appendRelativePath(in AString relativeFilePath);
    [noscript] void appendRelativeNativePath(in ACString relativeFilePath);
    
    /**
     *  Accessor to a null terminated string which will specify
     *  the file in a persistent manner for disk storage.
     *
     *  The character set of this attribute is undefined.  DO NOT TRY TO
     *  INTERPRET IT AS HUMAN READABLE TEXT!
     */
    [must_use] attribute ACString persistentDescriptor;

    /**
     *  reveal
     *
     *  Ask the operating system to open the folder which contains
     *  this file or folder. This routine only works on platforms which
     *  support the ability to open a folder and is run async on Windows.
     *  This routine must be called on the main.
     */
    [must_use] void reveal();

    /**
     *  launch
     *
     *  Ask the operating system to attempt to open the file.
     *  this really just simulates "double clicking" the file on your platform.
     *  This routine only works on platforms which support this functionality
     *  and is run async on Windows.  This routine must be called on the
     *  main thread.
     */
    [must_use] void launch();

    /**
     *  getRelativeDescriptor
     *
     *  Returns a relative file path in an opaque, XP format. It is therefore
     *  not a native path.
     *
     *  The character set of the string returned from this function is
     *  undefined.  DO NOT TRY TO INTERPRET IT AS HUMAN READABLE TEXT!
     *
     *   @param fromFile
     *       the file from which the descriptor is relative.
     *       Throws if fromFile is null.
     */
    [must_use] ACString getRelativeDescriptor(in nsIFile fromFile);

    /**
     *  setRelativeDescriptor
     *
     *  Initializes the file to the location relative to fromFile using
     *  a string returned by getRelativeDescriptor.
     *
     *   @param fromFile
     *       the file to which the descriptor is relative
     *   @param relative
     *       the relative descriptor obtained from getRelativeDescriptor
     */
    [must_use]
    void setRelativeDescriptor(in nsIFile fromFile, in ACString relativeDesc);

    /**
     *  getRelativePath
     *
     *  Returns a relative file from 'fromFile' to this file as a UTF-8 string.
     *  Going up the directory tree is represented via "../".  '/' is used as
     *  the path segment separator.  This is not a native path, since it's UTF-8
     *  encoded.
     *
     *   @param fromFile
     *       the file from which the path is relative.
     *       Throws if fromFile is null.
     */
    [must_use] AUTF8String getRelativePath(in nsIFile fromFile);

    /**
     *  setRelativePath
     *
     *  Initializes the file to the location relative to fromFile using
     *  a string returned by getRelativePath.
     *
     *   @param fromFile
     *       the file from which the path is relative
     *   @param relative
     *       the relative path obtained from getRelativePath
     */
    [must_use]
    void setRelativePath(in nsIFile fromFile, in AUTF8String relativeDesc);
};

%{C++
#ifdef MOZILLA_INTERNAL_API
#include "nsDirectoryServiceUtils.h"
#endif
%}