Tar Component

Properties   Methods   Events   Config Settings   Errors  

The Tar component implements a tar archive utility, compatible with the UNIX tar and untar utilities. The component supports the old v7 tar format. The component also implements gzip compression and can be used to create or decompress .tar.gz archives.

Syntax

TipzTar

Remarks

The interface is identical to that of the Zip component, and is the same whether gzip compression is used or not. In particular, the Compress method is used to create tar archives, even if actual compression is not used.

To create a new archive, first set the ArchiveFile property to the name of the archive to be created. Then, specify the files to be compressed either by invoking IncludeFiles, or by adding a new object to the Files collection and setting the values of the DecompressedName and CompressedName. fields. Finally, call the Compress method to create the archive.

To decompress an existing archive, set ArchiveFile to the name of the archive to be decompressed. The ExtractToPath property may be set, and then calling the ExtractAll method will decompress all files in the archive to this path.

For finer control, the Scan method should be used to read the file information stored in the archive. This will fill out the information in the Files collection. The values of DecompressedName may then be changed if desired. Finally, ExtractAll may be used to decompress the entire archive, or Extract may be used for finer control.

Data may be streamed out by setting WriteToProgressEvent to true. Then, the Progress event may be trapped to retrieve the data.

tar.gz files may be created or extracted by setting the UseGzipCompression property to true. When Compress is invoked, this will cause all output to be streamed through a gzip compressor as it is written. When extracting or scanning the tar archive will automatically be decompressed and written temporarily to disk. Note that this might cause Scan, Extract, and ExtractAll to operate slowly without firing events.

.gz files may also be compressed or decompressed using the Gzip component.

Example (Creating a Tar File)

ZipControl.ArchiveFile = "c:\test.tar.gz" ZipControl.RecurseSubdirectories = true ZipControl.UseGzipCompression = true ZipControl.IncludeFiles("c:\foo\*") ZipControl.Compress() Example (Extracting from a Tar File)

ZipControl.ArchiveFile = "c:\temp.tar" ZipControl.UseGzipCompression = false ZipControl.ExtractToPath = "c:\extracted\" ZipControl.ExtractAll()

Property List

---

The following is the full list of the properties of the component with short descriptions. Click on the links for further details.

Method List

---

The following is the full list of the methods of the component with short descriptions. Click on the links for further details.

Event List

---

The following is the full list of the events fired by the component with short descriptions. Click on the links for further details.

Config Settings

---

The following is a list of config settings for the component with short descriptions. Click on the links for further details.

ArchiveFile Property (Tar Component)

The name of the zip, gzip, tar, or jar archive.

Syntax

property ArchiveFile: String read get_ArchiveFile write set_ArchiveFile;

Default Value

''

Remarks

This property specifies the name of the archive to be read or written. This property is required when extracting files.

When Scan, Extract, or ExtractAll is invoked, the file specified by ArchiveFile will be opened for read. If the file does not exist, a trappable error will be generated.

When Compress is called, the file named by ArchiveFile will be written; if a file of this name already exists the Overwrite event will be fired. If ArchiveFile is set to the empty string (''), the archive will not be written to disk, and will be provided only through the Progress event.

The filename may be specified with or without a path. Paths may be relative or absolute, and should be specified in the format native to the host operating system. The filename should be specified with the appropriate extension (such as 'zip'); an extension will not automatically be appended by the component.

If the file cannot be read, or written, as appropriate, a trappable error will be generated.

Example (Creating an Archive)

ZipControl.ArchiveFile = "c:\test.zip" ZipControl.RecurseSubdirectories = true ZipControl.IncludeFiles("c:\foo\*") ZipControl.Compress()

Note: an archive already open for read may be closed by setting ArchiveFile to the empty string ('').

ExcludedFiles Property (Tar Component)

A list of files to exclude.

Syntax

property ExcludedFiles: String read get_ExcludedFiles write set_ExcludedFiles;

Default Value

''

Remarks

This property specifies files that should be excluded when Compress or Extract is invoked. When Compress is invoked, each value of DecompressedName in Files will be compared to ExcludedFiles, and each file will be excluded if the name matches. When Extract is called, each value of CompressedName in Files matching the parameter to Extract will be compared to ExcludedFiles, and will be excluded if appropriate. Calling the ExtractAll method will ignore this property and extract all files in the archive.

This property may be set to one or more filenames or directory names. Files may be specified with or without a path, and with or without wildcards. If a path is specified, files in the indicated directory will be excluded; subdirectories will be recursed into if RecurseSubdirectories is true. If no path is specified but wildcards are, matching files in all directories will be excluded. If a single filename without a path is specified, it must correspond exactly to the appropriate value of CompressedName or DecompressedName.

Directories should end with a slash ('/' or '\', as appropriate.) If a directory is specified, all files and subdirectories in the specified directory will be excluded.

A pipe character ('|') should be used to separate multiple file or directory names.

The following examples illustrate the use of the property:

Example

ZipControl.ArchiveFile = "c:\test.zip" ZipControl.IncludeFiles("c:\test\*") ZipControl.ExcludedFiles = "*.tmp" ZipControl.Compress() Example

ZipControl.ArchiveFile = "c:\test.tar" ZipControl.Scan() ZipControl.ExcludedFiles = "*.bak | backup/" ZipControl.ExtractToPath = "c:\temp" ZipControl.Extract("*") As per the examples, the property should be specified differently for compression and decompression. When invoking Compress, the format of ExcludedFiles should correspond to that of the local file system. When invoking Extract the format should correspond to standard (UNIX) format, and should not contain drive letters or backslashes.

You may exclude files based on their attributes as well: See the ExcludedAttributes configuration setting for more information.

If the property is set to the empty string, no files will be excluded. This property is never reset automatically, so be sure to reset it manually if using a single instance of the component for both compression and extraction. Failure to do so may result in I/O errors or unexpected results.

ExtractToPath Property (Tar Component)

A base path to decompress to.

Syntax

property ExtractToPath: String read get_ExtractToPath write set_ExtractToPath;

Default Value

''

Remarks

Setting the ExtractToPath property affects the operation of the Extract and ExtractAll methods. Setting this property to a nonempty string will cause all decompressed files to be written to the specified path. If pathnames are given in the values of DecompressedName they will be regarded as relative to ExtractToPath.

If the specified directory does not exist, it will be created when extraction is done.

ExtractToPath should always be specified in the format native to the host operating system, and with a trailing slash or backslash. If the path is specified otherwise, it will be immediately converted and stored in the converted format. For example, '/temp' would be immediately converted to '\temp\' on a Windows system.

Example (Extracting from an Archive)

ZipControl.ArchiveFile = "c:\temp.zip" ZipControl.ExtractToPath = "c:\extracted\" ZipControl.ExtractAll()

Example - Adding Files Dim i as Integer ZipControl.ArchiveFile = "c:\test.zip" ZipControl.Scan() For i = 0 to ZipControl.Files.Count - 1 ZipControl.Files(i).DecompressedName(i) = "c:\temp\" + ZipControl.Files(i).DecompressedName Next i ZipControl.ExtractToPath = "" ZipControl.ExtractAll() ZipControl.IncludeFiles("c:\extra\*") ZipControl.Compress()

Files Property (Tar Component)

Collection of Tar archive files.

Syntax

property Files: TipzTARFileList read get_Files write set_Files;

Remarks

When a compressed archive is scanned or decompressed, the values of this collection are populated accordingly.

When creating a compressed archive, this property may be used to set the files to be stored. For each entry added to the collection, the DecompressedName field should be set to the name of the file to be decompressed, and the CompressedName field should be set to the filename to store in the archive.

Archives may also be created using the IncludeFiles method. Invoking the IncludeFiles method causes the values of this collection to be filled out. These values may then be changed directly if desired.

Please refer to the TARFile type for a complete list of fields.

OverwriteFiles Property (Tar Component)

Whether or not to overwrite files.

Syntax

property OverwriteFiles: Boolean read get_OverwriteFiles write set_OverwriteFiles;

Default Value

true

Remarks

If this property is set to true, existing files will be overwritten when decompressing. When Extract or ExtractAll is called, each file specified in Files will be checked for existence. If a file exists, the Overwrite event will be fired, and the files will be overwritten if OverwriteFiles is set to true.

More precise control of which files should be overwritten may be gained by listening to the Overwrite event and altering its parameters when the event is fired.

This property only affects the operation of Extract and ExtractAll. When compressing files, ArchiveFile will always be overwritten unless the user specifies otherwise in the Overwrite event.

RecurseSubdirectories Property (Tar Component)

Whether or not to recurse into subdirectories.

Syntax

property RecurseSubdirectories: Boolean read get_RecurseSubdirectories write set_RecurseSubdirectories;

Default Value

true

Remarks

This property affects the behavior of IncludeFiles and Extract and the meaning of ExcludedFiles. If this property is set to true, IncludeFiles will recurse into all subdirectories whenever it performs a search on the file system.

Be sure RecurseSubdirectories is set to the appropriate value before invoking IncludeFiles, Extract, or Compress; changing the value of this property after method calls will not retroactively alter their effects.

Example (Creating an Archive)

ZipControl.ArchiveFile = "c:\test.zip" ZipControl.RecurseSubdirectories = true ZipControl.IncludeFiles("c:\foo\*") ZipControl.Compress()

TarData Property (Tar Component)

(Decompression only) The tar file contents as a byte array.

Syntax

property TarData: String write set_TarData;
property TarDataB: TBytes write set_TarDataB;

Default Value

''

Remarks

Normally you should set ArchiveFile before invoking Scan or Extract. If you prefer to read the tar file from memory you may set TarData instead. TarData should be set to the entire contents of the tar file; this will allow you to read from the archive without writing any temporary files to disk.

If you would like to extract data from the archive without ever writing to disk you should also set WriteToProgressEvent to true, and after invoking Scan, you should set the value of DecompressedName for each file in the Files collection to an empty string. Then, when you invoke Extract (or ExtractAll) the data will be provided in the Progress event.

This property is write-only. Note that modifying a tar file stored in TarData is not supported, so Append, Delete, etc., will throw exceptions.

This property is write-only and not available at design time.

UseGzipCompression Property (Tar Component)

Whether or not to use gzip compression.

Syntax

property UseGzipCompression: Boolean read get_UseGzipCompression write set_UseGzipCompression;

Default Value

false

Remarks

If this property is set to true, the component will operate on tar archives that have been compressed with gzip. The interface of the component remains the same. During compression, the data will be streamed through a gzip compressor as it is written to the file. During decompression, the component will unzip the data to a temporary tar archive, and then automatically scan or decompress the tar archive.

The creation of the temporary tar file will occur when the Scan method is invoked (note that this method is invoked automatically by Extract and ExtractAll if it is not invoked explicitly by the user). The entire file must be decompressed, so Scan might operate slowly, and the Progress event will be fired as the tar file is extracted. If Scan is invoked automatically by Extract or ExtractAll, the PercentProcessed parameter of the event will increase from 0 to 100 as the archive is decompressed, and again as files are extracted from the temporary file.

The temporary file will automatically be deleted by the component after it is no longer needed. To extract the tar file itself (rather than its contents), the Gzip component should be used.

Due to the nature of the gzip format, Append and Delete are not supported for .tar.gz files.

If this property is set to false, the component will create and read ordinary, uncompressed tar archives.

NOTE: This is not supported when using an input stream for extraction.

Abort Method (Tar Component)

Aborts the current operation.

Syntax

procedure Abort();

Remarks

Abort may be used to immediately interrupt compression or decompression. Any files partially written by the component will be deleted.

In case Append or Delete is aborted the archive will be left in its original state.

Append Method (Tar Component)

Adds a file to an existing archive.

Syntax

procedure Append(DecompressedName: String; CompressedName: String);

Remarks

Append may be used to add a file to an existing archive. Unlike IncludeFiles, Append compresses and adds the file to the archive as soon as it is invoked.

DecompressedName should be set to the name of the single file to be added. It should be specified with a path if necessary, to allow the component to find it. The value of CompressedName is the name that will be stored in the archive.

When Append is invoked, the Scan method will first be invoked, if it has not been invoked already. Note that if IncludeFiles has been invoked, or if the values of CompressedName and DecompressedName have been set for that file in the Files collection, this information will be reset by the call to Scan.

After the file is added, the array properties will be updated appropriately.

This method may only be used to add a file to an existing archive. To add files to a new archive, the IncludeFiles and Compress methods should be used.

Due to the nature of the gzip format, Append and Delete are not supported for .tar.gz files.

Compress Method (Tar Component)

Creates the compressed archive.

Syntax

procedure Compress();

Remarks

Invoking Compress creates the archive specified by ArchiveFile. When the method is called, all files specified by the DecompressedName field of the Files collection will be compressed and written to ArchiveFile.

The compressed data may be streamed out by setting WriteToProgressEvent to true. If streaming is enabled the compressed data will also be provided via the Progress event. If ArchiveFile is set to an empty string the archive will be written only to this event.

The files to compress are specified in the Files collection. The file names are specified by CompressedName and DecompressedName. These should be specified before invoking Compress, either manually or by invoking IncludeFiles.

The BeginFile and EndFile events will be fired as files are processed, and the Progress event will be fired as data is compressed.

Existing files will be overwritten by the component if OverwriteFiles is set to true. Finer control over which files are overwritten may be gained by trapping the Overwrite event.

Example (Creating an Archive)

ZipControl.ArchiveFile = "c:\test.zip" ZipControl.RecurseSubdirectories = true ZipControl.IncludeFiles("c:\foo\*") ZipControl.Compress()

Config Method (Tar Component)

Sets or retrieves a configuration setting.

Syntax

function Config(ConfigurationString: String): String;

Remarks

Config is a generic method available in every component. It is used to set and retrieve configuration settings for the component.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

Delete Method (Tar Component)

Deletes one or more files from an existing archive.

Syntax

procedure Delete(FileNames: String);

Remarks

Delete deletes one or more files from an existing archive, without reprocessing the compressed data. The archive will be opened immediately, and the file(s) will immediately be removed permanently from the archive.

The list of filenames should be specified exactly as when calling Extract:

Filenames may be set to one or more filenames or directory names. Files may be specified with or without a path, and with or without wildcards. If a path is specified, files in the indicated directory will be affected; subdirectories will be recursed into if RecurseSubdirectories is true. If no path is specified but wildcards are, matching files in all directories will be affected. If a single filename without a path is specified, it must correspond exactly to the appropriate value of CompressedName.

Directories should end with a slash ('/'). If a directory is specified, all files and subdirectories in the specified directory will be affected.

A pipe character ('|') should be used to separate multiple file or directory names. Alternatively, the method may be invoked repeatedly.

The ExcludedFiles property may be used to further limit the files to be deleted. When Delete is used to delete a directory or match wildcards, each file to be deleted is first compared against ExcludedFiles, and any files marked as excluded will not be deleted. When Delete is used to delete a single file, the value of ExcludedFiles will be ignored.

When the method is invoked, the Scan method will first be invoked, if it has not been invoked already. Note that if IncludeFiles has been invoked, or if the values of CompressedName and DecompressedName for each file in the Files collection have been set, this information will be reset by the call to Scan.

When deleting multiple files, the component will operate most efficiently if all filenames are passed to Delete in a single invocation of the method. Invoking Delete repeatedly on large archives is not recommended.

Invoking Delete will only remove files from ArchiveFile; it will not delete the files from the disk.

Example

ZipControl.ArchiveFile = "c:\\test.zip" ZipControl.Delete("default_readme.txt"); ZipControl.Append("\\mydir\\my_readme.txt", "my_readme.txt")

Extract Method (Tar Component)

Extracts a single file, directory, or group of files, from the archive.

Syntax

procedure Extract(FileNames: String);

Remarks

Extract extracts one or more files from the archive. The file(s) will be extracted to the directory specified by ExtractToPath, and given the names found in the archive or specified by the DecompressedName of the file in the Files collection.

Filenames may be set to one or more filenames or directory names. Files may be specified with or without a path, and with or without wildcards. If a path is specified, files in the indicated directory will be affected; subdirectories will be recursed into if RecurseSubdirectories is true. If no path is specified but wildcards are, matching files in all directories will be affected. If a single filename without a path is specified, it must correspond exactly to the appropriate value of CompressedName.

Directories should end with a slash ('/'). If a directory is specified, all files and subdirectories in the specified directory will be affected.

A pipe character ('|') should be used to separate multiple file or directory names. Alternatively, the method may be invoked repeatedly.

The ExcludedFiles property may be used to further limit the files to be extracted. When Extract is used to extract a directory or match wildcards, each file to be extracted is first compared against ExcludedFiles, and any files marked as excluded will not be extracted. When Extract is used to extract a single file, the value of ExcludedFiles will be ignored.

To extract all files in the archive, the ExtractAll method may be used.

The BeginFile and EndFile events will be fired before and after each file is extracted, and the Progress event will be fired as the data is extracted. If WriteToProgressEvent is set to true, the decompressed data will be streamed out through the Progress event.

Example

ZipControl.ArchiveFile = "c:\test.tar" ZipControl.ExcludedFiles = "*.bak | backup/" ZipControl.ExtractToPath = "c:\temp" ZipControl.Extract("*") Example ZipControl.ArchiveFile = "c:\test.zip" ZipControl.ExcludedFiles = "" ZipControl.ExtractToPath = "c:\temp" ZipControl.Extract("code/") Example ZipControl.ArchiveFile = "c:\test.jar" ZipControl.ExcludedFiles = "*.txt" ZipControl.ExtractToPath = "c:\" ZipControl.Extract("* | docs/readme.txt")

ExtractAll Method (Tar Component)

Extracts all files from the compressed archive.

Syntax

procedure ExtractAll();

Remarks

ExtractAll extracts all files from the archive. The file(s) will be extracted to the directory specified by ExtractToPath, and given the names found in the archive or specified by the DecompressedName field of the file in the Files collection.

If Scan has not been invoked when ExtractAll is called, Scan will automatically be invoked, and the Files collection will be set to the values found in the archive. To manually set the decompressed filenames, Scan should be invoked before setting the DecompressedName field.

Invoking this method is equivalent to setting ExcludedFiles to the empty string, and then invoking Extract with '*' as the argument. Calling this method will cause the ExcludedFiles property to be ignored; to extract all files except those specified by ExcludedFiles, call the Extract method with the wildcard "*" as the method parameter instead of calling this method.

The BeginFile and EndFile events will be fired before and after each file is extracted, and the Progress event will be fired as the data is extracted. If WriteToProgressEvent is set to true, the decompressed data will be streamed out through the Progress event.

Example (Extracting from an Archive)

ZipControl.ArchiveFile = "c:\temp.zip" ZipControl.ExtractToPath = "c:\extracted\" ZipControl.ExtractAll()

IncludeFiles Method (Tar Component)

Specifies that the indicated files should be added to the archive.

Syntax

procedure IncludeFiles(FileNames: String);

Remarks

IncludeFiles may be used before Compress, to specify the files to be compressed. Invoking this method populates the Files collection accordingly.

Invoking the method does not create or alter the archive.

The argument should be a pipe ("|") -delimited sequence of one or more filenames. The filenames should be specified with paths if necessary, so that the files may be found on the local file system. The filenames will be stored as is in the DecompressedName field, and without a pathname in the CompressedName field of the Files collection.

Filenames may include the wildcards '?', '*', and '[ .. ]'. '?' will match any single character, and '*' will match an arbitrary sequence of characters. '[ .. ]' may be used to match any of the characters inside, or a range, such as '[a-z]'. A '\' can be used to escape wildcard characters.

If wildcards are specified, the file system will be scanned and all files matching the specified mask will be added. Moreover, subdirectories will be recursed into if RecurseSubdirectories is set to true. When recursing into subdirectories, relative path information will be stored in CompressedName field of the Files collection.

The ExcludedFiles may be used to limit the files to be compressed. This property is checked when Compress is invoked, rather than when IncludeFiles is invoked, so this property may be set before or after invoking IncludeFiles.

Note that invoking IncludeFiles will not reset the component, or remove old values of CompressedName and DecompressedName. This may be done by first clearing the Files collection.

Example

ZipControl.IncludeFiles("c:\test\* | c:\readme") ZipControl.ExcludedFiles = "*.tmp" ZipControl.Compress()

Reset Method (Tar Component)

Resets the component.

Syntax

procedure Reset();

Remarks

Reset resets the state of the component. The Files collection will be cleared, all properties will be set to their default values, and any files open will be closed.

Scan Method (Tar Component)

Scans the compressed archive.

Syntax

procedure Scan();

Remarks

This method will scan the archive specified by ArchiveFile. The number of files and their names and sizes will be determined and written to the Files collection.

After scanning the archive, the values of DecompressedName may be changed if desired, and any number of files may be decompressed. The Extract method allows you to decompress files of your choice, and the ExtractAll method will decompress the entire archive.

Changing the values of the CompressedName field or the number of files in the Files collection will invalidate the scan. If either of these is changed and Extract or ExtractAll is then called; Scan will automatically be called again, and these values will be reset to their original values.

Calling this method will frequently generate a trappable error if the archive is corrupt. This is not guaranteed, however, as Scan only examines the headers.

Example

Dim i As Integer ZipControl.ArchiveFile = "c:\temp.zip" ZipControl.Scan For i = 0 To ZipControl.FileCount - 1 Debug.Print "File Name: " & ZipControl.FileDecompressedName(i) Debug.Print "File Size: " & ZipControl.FileDecompressedSize(i) Next i

SetArchiveInputStream Method (Tar Component)

The stream to read the zip, tar, jar, or gzip archive from.

Syntax

procedure SetArchiveInputStream(ArchiveStream: TStream);

Remarks

This method should be set when the archive is to be read from a stream when Extract is called.

By default, and when this is set to null, the component will read from the file specified by ArchiveFile. However, when this is a valid stream, the data will be read from the stream.

SetArchiveOutputStream Method (Tar Component)

The stream to write the zip, tar, jar, or gzip archive to.

Syntax

procedure SetArchiveOutputStream(ArchiveStream: TStream);

Remarks

This method should be set when the archive is to be written to a stream when Compress is called.

By default, and when this is set to null, the component will write to the file specified by ArchiveFile. However, when this is a valid stream, the data will be written to the stream.

BeginFile Event (Tar Component)

Fired before each file is processed.

Syntax

type TBeginFileEvent = procedure (
  Sender: TObject;
  Index: Integer;
  var Skip: Boolean
) of Object;

property OnBeginFile: TBeginFileEvent read FOnBeginFile write FOnBeginFile;

Remarks

BeginFile is fired before each file is processed by the compressor or decompressor, as appropriate. Index contains the array index of the file about to be processed, and the CompressedName, DecompressedName, CompressedSize (decompression only), and DecompressedSize fields of the Files collection for this index contain more detailed information about the file about to be processed.

When extracting, an alternate location may be specified by trapping the event, and modifying DecompressedName and/or ExtractToPath. If DecompressedName is set to an empty string, the file will not be written to disk. If WriteToProgressEvent is true, the file will still be decompressed, and the data may be extracted through the Progress event.

This event may also be trapped while compressing. CompressedName and DecompressedName may be changed.

You may set the Skip parameter to true in order to skip the file completely while compressing or extracting.

EndFile Event (Tar Component)

Fired after each file is processed.

Syntax

type TEndFileEvent = procedure (
  Sender: TObject;
  Index: Integer
) of Object;

property OnEndFile: TEndFileEvent read FOnEndFile write FOnEndFile;

Remarks

EndFile is fired after each file is processed by the compressor or decompressor, as appropriate. Index contains the array index of the file processed, and the CompressedName, DecompressedName, CompressedSize, and DecompressedSize fields in the Files collection for this index contain more detailed information about the file processed.

Error Event (Tar Component)

Information about non-fatal errors.

Syntax

type TErrorEvent = procedure (
  Sender: TObject;
  const Description: String;
  ErrorCode: Integer;
  Index: Integer;
  const Filename: String;
  var Ignore: Boolean
) of Object;

property OnError: TErrorEvent read FOnError write FOnError;

Remarks

The Error event is fired when non-fatal errors occur during compression or decompression. Note that if this event is fired during decompression this may indicate that the archive is corrupt.

By default these errors will cause the component to fail with an exception. The exception may be overridden by setting Ignore to true. This will cause the error to be ignored, the file will be skipped if necessary, and the component will continue operation.

ErrorCode will correspond to one of the following errors:

Description contains a textual description of the error. Index and Filename contain the array index (where appropriate) and filename of the file being processed at the time of the error.

Overwrite Event (Tar Component)

Fired whenever a file exists and may be overwritten.

Syntax

type TOverwriteEvent = procedure (
  Sender: TObject;
  var Filename: String;
  var Overwrite: Boolean
) of Object;

property OnOverwrite: TOverwriteEvent read FOnOverwrite write FOnOverwrite;

Remarks

Overwrite is fired when a file is about to be overwritten, and would overwrite an existing file. The event is fired during decompression.

Filename contains the full name of the file, specified with its pathname.

Overwrite specifies whether or not the file will be overwritten. For Zip, Jar, and Tar, this is equal by default to the value of the OverwriteFiles property. For Gzip, this value defaults to true.

Either of the parameters may be changed when the event is fired. Changing the value of Overwrite will override the default behavior of the component, and cause the file to be overwritten or not overwritten, depending on the value set. If Filename is changed, the value of Overwrite will be ignored, and the file will be written with the specified name. If a file of the new name also exists this file will be silently overwritten.

Progress Event (Tar Component)

Fired as progress is made.

Syntax

type TProgressEvent = procedure (
  Sender: TObject;
  const Data: String;
  const DataB: TBytes;
  const Filename: String;
  BytesProcessed: Int64;
  PercentProcessed: Integer
) of Object;

property OnProgress: TProgressEvent read FOnProgress write FOnProgress;

Remarks

The Progress event is automatically fired as compression or decompression is performed. When WriteToProgressEvent is true, the output data is provided through the Data parameter, allowing for it to be streamed out.

Filename contains the name of the file being written. If no file is being written, Filename will contain an empty string, and the output data will be provided exclusively through this event.

BytesProcessed contains the total number of uncompressed bytes processed. PercentProcessed contains the percent of uncompressed bytes processed, corresponding roughly to the running time of the operation.

For Gzip extraction only, BytesProcessed and PercentProcessed will reflect the number of compressed bytes extracted, as it is generally impossible to predetermine the total uncompressed size.

If WriteToProgressEvent is false, Data will contain null.

TARFile Type

The Tar file in the archive.

Remarks

This type contains information about the Tar file that either exists in the archive or is being added to the archive.

Fields

Constructors

constructor Create();

constructor Create(valDecompressedName: String);

constructor Create(valCompressedName: String; valDecompressedName: String);

Config Settings (Tar Component)

The component accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

Tar Config Settings

Base Config Settings

Trappable Errors (Tar Component)

Errors

The following errors may be generated by the component. Note that frequently the error message will contain more specific information than what is listed here.

Note that some non-fatal errors may be trapped and explicitly ignored in the Error event. This will allow the component to continue operation even in case of error.

Tar Errors