Implement eager pkg-config provider

This implements provider that generates modules based on all .pc files
present in system. This allows to get rid of the multi-shot providers
such as fallback provider.

Fixes: QBS-1614
Change-Id: Icf87ac609bc34bd26e8ed94ae547a7e649835a3a
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

3 files changed, 106 insertions, 0 deletions

diff --git a/doc/qbs.qdoc b/doc/qbs.qdoc
index ac7bf20c2..f297ea2cf 100644
--- a/doc/qbs.qdoc
+++ b/doc/qbs.qdoc
@@ -81,6 +81,7 @@
                 \li \l{List of Built-in Services}
                 \li \l{Command-Line Interface}
                 \li \l{List of Modules}
+                \li \l{List of Module Providers}
                 \li \l{Command and JavaScriptCommand}
            \endlist
 
diff --git a/doc/reference/module-providers/qbspkgconfig-module-provider.qdoc b/doc/reference/module-providers/qbspkgconfig-module-provider.qdoc
new file mode 100644
index 000000000..80afe3667
--- /dev/null
+++ b/doc/reference/module-providers/qbspkgconfig-module-provider.qdoc
@@ -0,0 +1,99 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 Ivan Komissarov (abbapoh@gmail.com)
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qbs.
+**
+** $QT_BEGIN_LICENSE:FDL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Free Documentation License Usage
+** Alternatively, this file may be used under the terms of the GNU Free
+** Documentation License version 1.3 as published by the Free Software
+** Foundation and appearing in the file included in the packaging of
+** this file. Please review the following information to ensure
+** the GNU Free Documentation License version 1.3 requirements
+** will be met: https://www.gnu.org/licenses/fdl-1.3.html.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*!
+    \qmltype qbspkgconfig
+    \inqmlmodule QbsModuleProviders
+    \since 1.20
+
+    \brief Module provider based on the qbspkg-config library.
+
+    \QBS uses a built-in parser of the \c{*.pc} files and does not require the presence of the
+    \c pkg-config tool in the system. However, if the \c pkg-config tool is present, \QBS will
+    use the same libDirs as the system pkg-config uses by default; otherwise, a built-in list of
+    paths is used.
+
+    In order to enable usage of this provider in your Product, set the
+    \l{Product::qbsModuleProviders}{qbsModuleProviders} property as shown in the example below:
+    \snippet ../examples/pkgconfig-provider/pkgconfig-provider.qbs 0
+*/
+
+/*!
+    \qmlproperty string qbspkgconfig::executableFilePath
+
+    The path to the \c {pkg-config} executable. If not set, the pkg-config from PATH is used.
+
+    \defaultvalue undefined
+*/
+
+/*!
+    \qmlproperty stringList qbspkgconfig::libDirs
+
+    Set this if you need to overwrite the default search directories.
+    \note You do not need to set this for cross-compilation in order to point
+          to the sysroot. \QBS does that for you.
+
+    This property is the equivalent of the \c{PKG_CONFIG_PATH} / \c{PKG_CONFIG_LIBDIR} variables
+    for the \c{pkg-config} tool.
+
+    \nodefaultvalue
+*/
+
+/*!
+    \qmlproperty bool qbspkgconfig::staticMode
+
+    If this property is \c true, then \QBS will include "private" libs and dependencies of the
+    package. This property is the equivalent of the
+    \c{--static} option for the \c{pkg-config} tool.
+
+    Set this if your product is to be linked statically.
+
+    \defaultvalue \c false
+*/
+
+/*!
+    \qmlproperty path qbspkgconfig::sysroot
+
+    Set this property if you need to overwrite the default search sysroot path used by
+    \c pkg-config.
+
+    This can be useful if \c pkg-config files are located in the directory other than qbs.sysroot.
+    This is the case on macOS platform - all XCode profiles are sysrooted to the SDK
+    directory, but \c pkg-config is typically intalled using Brew and resides in the
+    \c /usr/local directory.
+
+    Setting this property to \c undefined or empty (\c "") value will use pkg-config's default
+    search paths:
+    \code
+        qbs build module-providers.pkgconfig.sysroot:undefined
+    \endcode
+
+    This property is the equivalent of the \c{PKG_CONFIG_SYSROOT_DIR} variable for the
+    \c{pkg-config} tool.
+
+    \defaultvalue \c "" on macOS, \c qbs.sysroot on other platforms
+*/
diff --git a/doc/reference/reference.qdoc b/doc/reference/reference.qdoc
index 63b8c187d..f2992b287 100644
--- a/doc/reference/reference.qdoc
+++ b/doc/reference/reference.qdoc
@@ -75,6 +75,12 @@
 */
 
 /*!
+    \qmlmodule QbsModuleProviders
+    \title List of Module Providers
+    These are the module providers shipped with \QBS.
+*/
+
+/*!
     \group list-of-items
     \title List of All Items