Use an attribute from another XML in a different attribute in another XML

Question

I use Heat from Wix toolset to generate components for my installer but few of my installers are a Per-User and such i cannot use Heat's Autogenerate Guids. I can randomly generate a GUID but i don't want that because of components rules.

So I have an XML with list of files that should be included in the Installations in different structure than the generated one into which i have added static guids for each file. What i want to do is match the filename between my XML and generated XML and insert the GUID into my generated XML.

Here is a sample of the xml without any transformation:

<?xml version="1.0" encoding="utf-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">
    <Fragment>
        <DirectoryRef Id="Dir_Sample">
            <Directory Id="Folder1" Name="Folder1">
                <Component Id="NewTextFile0.txt" Guid="PUT-GUID-HERE">
                    <File Id="NewTextFile0.txt" KeyPath="yes" Source="$(var.sample)\Folder1\NewTextFile0.txt" />
                </Component>
            </Directory>
        </DirectoryRef>
    </Fragment>
    <Fragment>
        <ComponentGroup Id="CG_Sample">
            <ComponentRef Id="NewTextFile0.txt" />
        </ComponentGroup>
    </Fragment>
</Wix>

Here is my custom XML with GUIDs for each File:

<?xml version="1.0" encoding="utf-8"?>
<FileSystemList>
  <File Path="\Programs\Folder1\NewTextFile0.txt" Guid="52B62A6E-DD87-424A-8296-3AA00E74AEF8" />
</FileSystemList>

So i want Guid="PUT-GUID-HERE" be replaced with Guid="52B62A6E-DD87-424A-8296-3AA00E74AEF8" when the filename and preferably the parent folder matches on both XMLs.

I'm trying to understand XSL but all i'm able to achieve is hair loss. I and my remaining hair will appreciate any help.

Update: Matching between these two xml files should be performed on Source of the first file and Path of the second file.

Source="$(var.sample)\Folder1\NewTextFile0.txt" The file name (NewTextFile0.txt) and the parent folder (Folder1) together are unique in a project. The same goes for Path="\Programs\Folder1\NewTextFile0.txt" File name and parent folder being unique.

Answer 1

Try something like:

<xsl:stylesheet version="1.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:wi="http://schemas.microsoft.com/wix/2006/wi">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:strip-space elements="*"/>

<!-- identity transform -->
<xsl:template match="@*|node()">
    <xsl:copy>
        <xsl:apply-templates select="@*|node()"/>
    </xsl:copy>
</xsl:template>

<!-- insert GUID -->    
<xsl:template match="wi:Component/@Guid">
    <xsl:variable name="path" select="concat(../../@Name, '\', ../@Id)" />
    <xsl:attribute name="Guid">
        <xsl:value-of select="document('FileList.xml')/FileSystemList/File[contains(@Path, $path)]/@Guid"/>
    </xsl:attribute>
</xsl:template>

</xsl:stylesheet>

---

Edit:

To base the match on the contents of Component/File/@Source, change the definition of the $pathvariable to:

<xsl:variable name="path" select="substring-after(../wi:File/@Source, ')')" />

This is assuming that anything in the Source attribute that comes after the first ")" is part of the path stored in the other file.