既然您决定使用通用的版本字符串模式,那么您需要一个函数来解析和比较安装程序中的版本字符串和从您网站下载的版本字符串。由于Inno Setup中没有内置这样的函数,因此您需要自己编写一个。
我看到了一些比较版本字符串的函数,例如在this script
中使用的函数,但我决定编写自己的函数。它可以检测无效的版本字符串,并将缺少的版本块视为0,这会导致像以下这样的版本字符串的比较是相等的:
1.2.3
1.2.3.0.0.0
以下脚本可能实现你想要的功能(设置版本由AppVersion
指令定义):
[Setup]
AppName=My Program
AppVersion=1.2.3
DefaultDirName=\My Program
[Code]
const
SetupURL = 'http://dex.wotanksmods.com/setup.exe';
VersionURL = 'http://dex.wotanksmods.com/latestver.txt';
type
TIntegerArray = array of Integer;
TCompareResult = (
crLesser,
crEquals,
crGreater
);
function Max(A, B: Integer): Integer;
begin
if A > B then Result := A else Result := B;
end;
function CompareValue(A, B: Integer): TCompareResult;
begin
if A = B then
Result := crEquals
else
if A < B then
Result := crLesser
else
Result := crGreater;
end;
function AddVersionChunk(const S: string; var A: TIntegerArray): Integer;
var
Chunk: Integer;
begin
Chunk := StrToIntDef(S, -1);
if Chunk <> -1 then
begin
Result := GetArrayLength(A) + 1;
SetArrayLength(A, Result);
A[Result - 1] := Chunk;
end
else
RaiseException('Invalid format of version string');
end;
function ParseVersionStr(const S: string; var A: TIntegerArray): Integer;
var
I: Integer;
Count: Integer;
Index: Integer;
begin
Count := 0;
Index := 1;
for I := 1 to Length(S) do
begin
case S[I] of
'.':
begin
AddVersionChunk(Copy(S, Index, Count), A);
Count := 0;
Index := I + 1;
end;
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
begin
Count := Count + 1;
end;
else
RaiseException('Invalid char in version string');
end;
end;
Result := AddVersionChunk(Copy(S, Index, Count), A);
end;
function GetVersionValue(const A: TIntegerArray; Index,
Length: Integer): Integer;
begin
Result := 0;
if (Index >= 0) and (Index < Length) then
Result := A[Index];
end;
function CompareVersionStr(const A, B: string): TCompareResult;
var
I: Integer;
VerLenA, VerLenB: Integer;
VerIntA, VerIntB: TIntegerArray;
begin
Result := crEquals;
VerLenA := ParseVersionStr(A, VerIntA);
VerLenB := ParseVersionStr(B, VerIntB);
for I := 0 to Max(VerLenA, VerLenB) - 1 do
begin
Result := CompareValue(GetVersionValue(VerIntA, I, VerLenA),
GetVersionValue(VerIntB, I, VerLenB));
if Result <> crEquals then
Exit;
end;
end;
function DownloadFile(const URL: string; var Response: string): Boolean;
var
WinHttpRequest: Variant;
begin
Result := True;
try
WinHttpRequest := CreateOleObject('WinHttp.WinHttpRequest.5.1');
WinHttpRequest.Open('GET', URL, False);
WinHttpRequest.Send;
Response := WinHttpRequest.ResponseText;
except
Result := False;
Response := GetExceptionMessage;
end;
end;
function InitializeSetup: Boolean;
var
ErrorCode: Integer;
SetupVersion: string;
LatestVersion: string;
begin
Result := True;
if DownloadFile(VersionURL, LatestVersion) then
begin
SetupVersion := '{#SetupSetting('AppVersion')}';
if CompareVersionStr(LatestVersion, SetupVersion) = crGreater then
begin
if MsgBox('There is a newer version of this setup available. Do ' +
'you want to visit the site ?', mbConfirmation, MB_YESNO) = IDYES then
begin
Result := not ShellExec('', SetupURL, '', '', SW_SHOW, ewNoWait,
ErrorCode);
end;
end;
end;
end;