使用StgOpenStorage以只读方式打开OLE Compound Documents [英] Opening OLE Compound Documents read-only with StgOpenStorage

问题描述

我正在XP下使用StgOpenStorage API来读取OLE复合文档，但是我找不到正确的标记组合来告诉Windows我只需要读取而不会阻塞可以通过其他任何方式访问它...
现在我正在使用STGM_READ | STGM_EXCLUSIVE，但是很明显，如果同时尝试从另一个应用程序打开文件，它会抱怨访问被拒绝..所以我尝试了STGM_READ | STGM_SHARE_DENY_NONE 但它抱怨标志无效.

I'm using the StgOpenStorage API under XP to read an OLE Compound Document, but I can't find the right mix of flags to tell Windows that I need just to read the file without blocking access to it to any other process...
Right now I'm using STGM_READ | STGM_EXCLUSIVE but obviously if at the same time I try to open the file from another application, it complains about denied access.. So I tried with STGM_READ | STGM_SHARE_DENY_NONE but it complains about invalid flags..

有没有办法做到这一点?我走错路了吗?

Is there a way to do this? Am I going the wrong way?

提前谢谢！

(如果相关，我正在通过pythoncom从Python调用API)

(I'm calling the API from Python via pythoncom, if it's relevant)

推荐答案

这是一个猜测，但来自StgOpenStorage API文档:

This is a guess, but from the StgOpenStorage API documentation:

指定STGM_DIRECT标志时，仅以下组合之一 可以从访问和共享组中指定标志的数量

When the STGM_DIRECT flag is specified, only one of the following combination of flags may be specified from the access and sharing groups

STGM_READ | STGM_SHARE_DENY_WRITE
STGM_READWRITE | STGM_SHARE_EXCLUSIVE
STGM_READ | STGM_PRIORITY

请注意，缺少STGM_TRANSACTED暗含了直接模式. 也就是说，如果既未指定STGM_DIRECT也未指定STGM_TRANSACTED，则STGM_DIRECT 是假定的.

Be aware that direct mode is implied by the absence of STGM_TRANSACTED. That is, if neither STGM_DIRECT nor STGM_TRANSACTED is specified, STGM_DIRECT is assumed.

这表明将标志更改为

STGM_READ | STGM_SHARE_DENY_NONE | STGM_TRANSACTED

应该做你想做的.这是有道理的:在直接"模式下，如果任何人都可以开始写入存储，那么他们将覆盖我们正在读取的内容.

should do what you want. This makes sense: in 'direct' mode, if anyone could start writing to the storage, then they would overwrite what we were reading.

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