core: Refactor initialization and how the default context is handled

Highlights for this change:

 - usbi_default_context is only set if libusb_init() is called with NULL.
 - All hotplug related functionality (e.g. initialization, processing) has been
   moved to hotplug.c
 - Backends are simplified by removing initialization mutexes. Mutual exclusion
   between init()/exit() is provided by default_context_lock.
 - Make hotplug types and functions part of libusbi.h with the common usbi_
   prefixes (removes hotplug.h).

Addresses issue highlighted in #855

Closes #856

Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>
Signed-off-by: Nathan Hjelm <hjelmn@google.com>

16 files changed, 0 insertions, 32 deletions

diff --git a/msvc/libusb_dll_2013.vcxproj b/msvc/libusb_dll_2013.vcxproj
index 56ffd75..03212dc 100644
--- a/msvc/libusb_dll_2013.vcxproj
+++ b/msvc/libusb_dll_2013.vcxproj
@@ -83,7 +83,6 @@
   <ItemGroup>
     <ClInclude Include=".\config.h" />
     <ClInclude Include="..\libusb\os\events_windows.h" />
-    <ClInclude Include="..\libusb\hotplug.h" />
     <ClInclude Include="..\libusb\libusb.h" />
     <ClInclude Include="..\libusb\libusbi.h" />
     <ClInclude Include="..\libusb\os\threads_windows.h" />
diff --git a/msvc/libusb_dll_2013.vcxproj.filters b/msvc/libusb_dll_2013.vcxproj.filters
index 8da28e3..c8643f2 100644
--- a/msvc/libusb_dll_2013.vcxproj.filters
+++ b/msvc/libusb_dll_2013.vcxproj.filters
@@ -21,9 +21,6 @@
     <ClInclude Include="..\libusb\os\events_windows.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="..\libusb\hotplug.h">
-      <Filter>Header Files</Filter>
-    </ClInclude>
     <ClInclude Include="..\libusb\libusb.h">
       <Filter>Header Files</Filter>
     </ClInclude>
diff --git a/msvc/libusb_dll_2015.vcxproj b/msvc/libusb_dll_2015.vcxproj
index d2c850d..f24d94b 100644
--- a/msvc/libusb_dll_2015.vcxproj
+++ b/msvc/libusb_dll_2015.vcxproj
@@ -84,7 +84,6 @@
   <ItemGroup>
     <ClInclude Include=".\config.h" />
     <ClInclude Include="..\libusb\os\events_windows.h" />
-    <ClInclude Include="..\libusb\hotplug.h" />
     <ClInclude Include="..\libusb\libusb.h" />
     <ClInclude Include="..\libusb\libusbi.h" />
     <ClInclude Include="..\libusb\os\threads_windows.h" />
diff --git a/msvc/libusb_dll_2015.vcxproj.filters b/msvc/libusb_dll_2015.vcxproj.filters
index 8da28e3..c8643f2 100644
--- a/msvc/libusb_dll_2015.vcxproj.filters
+++ b/msvc/libusb_dll_2015.vcxproj.filters
@@ -21,9 +21,6 @@
     <ClInclude Include="..\libusb\os\events_windows.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="..\libusb\hotplug.h">
-      <Filter>Header Files</Filter>
-    </ClInclude>
     <ClInclude Include="..\libusb\libusb.h">
       <Filter>Header Files</Filter>
     </ClInclude>
diff --git a/msvc/libusb_dll_2017.vcxproj b/msvc/libusb_dll_2017.vcxproj
index 598159d..2ff2f94 100644
--- a/msvc/libusb_dll_2017.vcxproj
+++ b/msvc/libusb_dll_2017.vcxproj
@@ -103,7 +103,6 @@
   <ItemGroup>
     <ClInclude Include=".\config.h" />
     <ClInclude Include="..\libusb\os\events_windows.h" />
-    <ClInclude Include="..\libusb\hotplug.h" />
     <ClInclude Include="..\libusb\libusb.h" />
     <ClInclude Include="..\libusb\libusbi.h" />
     <ClInclude Include="..\libusb\os\threads_windows.h" />
diff --git a/msvc/libusb_dll_2017.vcxproj.filters b/msvc/libusb_dll_2017.vcxproj.filters
index 8da28e3..c8643f2 100644
--- a/msvc/libusb_dll_2017.vcxproj.filters
+++ b/msvc/libusb_dll_2017.vcxproj.filters
@@ -21,9 +21,6 @@
     <ClInclude Include="..\libusb\os\events_windows.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="..\libusb\hotplug.h">
-      <Filter>Header Files</Filter>
-    </ClInclude>
     <ClInclude Include="..\libusb\libusb.h">
       <Filter>Header Files</Filter>
     </ClInclude>
diff --git a/msvc/libusb_dll_2019.vcxproj b/msvc/libusb_dll_2019.vcxproj
index dbd8717..266166e 100644
--- a/msvc/libusb_dll_2019.vcxproj
+++ b/msvc/libusb_dll_2019.vcxproj
@@ -103,7 +103,6 @@
   <ItemGroup>
     <ClInclude Include=".\config.h" />
     <ClInclude Include="..\libusb\os\events_windows.h" />
-    <ClInclude Include="..\libusb\hotplug.h" />
     <ClInclude Include="..\libusb\libusb.h" />
     <ClInclude Include="..\libusb\libusbi.h" />
     <ClInclude Include="..\libusb\os\threads_windows.h" />
diff --git a/msvc/libusb_dll_2019.vcxproj.filters b/msvc/libusb_dll_2019.vcxproj.filters
index 8da28e3..c8643f2 100644
--- a/msvc/libusb_dll_2019.vcxproj.filters
+++ b/msvc/libusb_dll_2019.vcxproj.filters
@@ -21,9 +21,6 @@
     <ClInclude Include="..\libusb\os\events_windows.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="..\libusb\hotplug.h">
-      <Filter>Header Files</Filter>
-    </ClInclude>
     <ClInclude Include="..\libusb\libusb.h">
       <Filter>Header Files</Filter>
     </ClInclude>
diff --git a/msvc/libusb_static_2013.vcxproj b/msvc/libusb_static_2013.vcxproj
index 1b287e5..94ba597 100644
--- a/msvc/libusb_static_2013.vcxproj
+++ b/msvc/libusb_static_2013.vcxproj
@@ -79,7 +79,6 @@
   <ItemGroup>
     <ClInclude Include=".\config.h" />
     <ClInclude Include="..\libusb\os\events_windows.h" />
-    <ClInclude Include="..\libusb\hotplug.h" />
     <ClInclude Include="..\libusb\libusb.h" />
     <ClInclude Include="..\libusb\libusbi.h" />
     <ClInclude Include="..\libusb\os\threads_windows.h" />
diff --git a/msvc/libusb_static_2013.vcxproj.filters b/msvc/libusb_static_2013.vcxproj.filters
index 2994ca1..a3294da 100644
--- a/msvc/libusb_static_2013.vcxproj.filters
+++ b/msvc/libusb_static_2013.vcxproj.filters
@@ -17,9 +17,6 @@
     <ClInclude Include="..\libusb\os\events_windows.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="..\libusb\hotplug.h">
-      <Filter>Header Files</Filter>
-    </ClInclude>
     <ClInclude Include="..\libusb\libusb.h">
       <Filter>Header Files</Filter>
     </ClInclude>
diff --git a/msvc/libusb_static_2015.vcxproj b/msvc/libusb_static_2015.vcxproj
index 9fa30da..f951523 100644
--- a/msvc/libusb_static_2015.vcxproj
+++ b/msvc/libusb_static_2015.vcxproj
@@ -80,7 +80,6 @@
   <ItemGroup>
     <ClInclude Include=".\config.h" />
     <ClInclude Include="..\libusb\os\events_windows.h" />
-    <ClInclude Include="..\libusb\hotplug.h" />
     <ClInclude Include="..\libusb\libusb.h" />
     <ClInclude Include="..\libusb\libusbi.h" />
     <ClInclude Include="..\libusb\os\threads_windows.h" />
diff --git a/msvc/libusb_static_2015.vcxproj.filters b/msvc/libusb_static_2015.vcxproj.filters
index 2994ca1..a3294da 100644
--- a/msvc/libusb_static_2015.vcxproj.filters
+++ b/msvc/libusb_static_2015.vcxproj.filters
@@ -17,9 +17,6 @@
     <ClInclude Include="..\libusb\os\events_windows.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="..\libusb\hotplug.h">
-      <Filter>Header Files</Filter>
-    </ClInclude>
     <ClInclude Include="..\libusb\libusb.h">
       <Filter>Header Files</Filter>
     </ClInclude>
diff --git a/msvc/libusb_static_2017.vcxproj b/msvc/libusb_static_2017.vcxproj
index 62076e0..857ee3f 100644
--- a/msvc/libusb_static_2017.vcxproj
+++ b/msvc/libusb_static_2017.vcxproj
@@ -99,7 +99,6 @@
   <ItemGroup>
     <ClInclude Include=".\config.h" />
     <ClInclude Include="..\libusb\os\events_windows.h" />
-    <ClInclude Include="..\libusb\hotplug.h" />
     <ClInclude Include="..\libusb\libusb.h" />
     <ClInclude Include="..\libusb\libusbi.h" />
     <ClInclude Include="..\libusb\os\threads_windows.h" />
diff --git a/msvc/libusb_static_2017.vcxproj.filters b/msvc/libusb_static_2017.vcxproj.filters
index 2994ca1..a3294da 100644
--- a/msvc/libusb_static_2017.vcxproj.filters
+++ b/msvc/libusb_static_2017.vcxproj.filters
@@ -17,9 +17,6 @@
     <ClInclude Include="..\libusb\os\events_windows.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="..\libusb\hotplug.h">
-      <Filter>Header Files</Filter>
-    </ClInclude>
     <ClInclude Include="..\libusb\libusb.h">
       <Filter>Header Files</Filter>
     </ClInclude>
diff --git a/msvc/libusb_static_2019.vcxproj b/msvc/libusb_static_2019.vcxproj
index 60ad642..036ce95 100644
--- a/msvc/libusb_static_2019.vcxproj
+++ b/msvc/libusb_static_2019.vcxproj
@@ -99,7 +99,6 @@
   <ItemGroup>
     <ClInclude Include=".\config.h" />
     <ClInclude Include="..\libusb\os\events_windows.h" />
-    <ClInclude Include="..\libusb\hotplug.h" />
     <ClInclude Include="..\libusb\libusb.h" />
     <ClInclude Include="..\libusb\libusbi.h" />
     <ClInclude Include="..\libusb\os\threads_windows.h" />
diff --git a/msvc/libusb_static_2019.vcxproj.filters b/msvc/libusb_static_2019.vcxproj.filters
index 2994ca1..a3294da 100644
--- a/msvc/libusb_static_2019.vcxproj.filters
+++ b/msvc/libusb_static_2019.vcxproj.filters
@@ -17,9 +17,6 @@
     <ClInclude Include="..\libusb\os\events_windows.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="..\libusb\hotplug.h">
-      <Filter>Header Files</Filter>
-    </ClInclude>
     <ClInclude Include="..\libusb\libusb.h">
       <Filter>Header Files</Filter>
     </ClInclude>