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Make wxFileSystemWatcher watch entries reference-counted.

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This helps to avoid problems that arise from watching the same physical file
system path multiple times, which could happen when adding a watch for a path
already watched because of a recursive watch on a parent directory, for
example.

Closes #14490.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72679 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Vadim Zeitlin
2012-10-15 01:08:37 +00:00
parent 227dee95e0
commit 76cfd1bf95
4 changed files with 85 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
include/wx/fswatcher.h
View File

@@ -196,7 +196,7 @@ class wxFSWatchInfo
{
public:
wxFSWatchInfo() :
m_events(-1), m_type(wxFSWPath_None)
m_events(-1), m_type(wxFSWPath_None), m_refcount(-1)
{
}
@@ -204,7 +204,8 @@ public:
int events,
wxFSWPathType type,
const wxString& filespec = wxString()) :
m_path(path), m_filespec(filespec), m_events(events), m_type(type)
m_path(path), m_filespec(filespec), m_events(events), m_type(type),
m_refcount(1)
{
}
@@ -225,11 +226,27 @@ public:
return m_type;
}
// Reference counting of watch entries is used to avoid watching the same
// file system path multiple times (this can happen even accidentally, e.g.
// when you have a recursive watch and then decide to watch some file or
// directory under it separately).
int IncRef()
{
return ++m_refcount;
}
int DecRef()
{
wxASSERT_MSG( m_refcount > 0, wxS("Trying to decrement a zero count") );
return --m_refcount;
}
protected:
wxString m_path;
wxString m_filespec; // For tree watches, holds any filespec to apply
int m_events;
wxFSWPathType m_type;
int m_refcount;
};
WX_DECLARE_STRING_HASH_MAP(wxFSWatchInfo, wxFSWatchInfoMap);

18
include/wx/private/fswatcher.h
View File

@@ -49,8 +49,13 @@ public:
virtual bool Add(const wxFSWatchInfo& winfo)
{
wxCHECK_MSG( m_watches.find(winfo.GetPath()) == m_watches.end(), false,
"Path '%s' is already watched");
if ( m_watches.find(winfo.GetPath()) != m_watches.end() )
{
wxLogTrace(wxTRACE_FSWATCHER,
"Path '%s' is already watched", winfo.GetPath());
// This can happen if a dir is watched, then a parent tree added
return true;
}
// construct watch entry
wxSharedPtr<wxFSWatchEntry> watch(new wxFSWatchEntry(winfo));
@@ -66,8 +71,13 @@ public:
virtual bool Remove(const wxFSWatchInfo& winfo)
{
wxFSWatchEntries::iterator it = m_watches.find(winfo.GetPath());
wxCHECK_MSG( it != m_watches.end(), false, "Path '%s' is not watched");
if ( it == m_watches.end() )
{
wxLogTrace(wxTRACE_FSWATCHER,
"Path '%s' is not watched", winfo.GetPath());
// This can happen if a dir is watched, then a parent tree added
return true;
}
wxSharedPtr<wxFSWatchEntry> watch = it->second;
m_watches.erase(it);
return DoRemove(watch);

38
src/common/fswatchercmn.cpp
View File

@@ -108,17 +108,28 @@ wxFileSystemWatcherBase::AddAny(const wxFileName& path,
if (canonical.IsEmpty())
return false;
wxCHECK_MSG(m_watches.find(canonical) == m_watches.end(), false,
wxString::Format("Path '%s' is already watched", canonical));
// adding a path in a platform specific way
wxFSWatchInfo watch(canonical, events, type, filespec);
if ( !m_service->Add(watch) )
return false;
// on success, add path to our 'watch-list'
wxFSWatchInfoMap::value_type val(canonical, watch);
return m_watches.insert(val).second;
// on success, either add path to our 'watch-list'
// or, if already watched, inc the refcount. This may happen if
// a dir is Add()ed, then later AddTree() is called on a parent dir
wxFSWatchInfoMap::iterator it = m_watches.find(canonical);
if ( it == m_watches.end() )
{
wxFSWatchInfoMap::value_type val(canonical, watch);
m_watches.insert(val).second;
}
else
{
wxFSWatchInfo& watch = it->second;
int count = watch.IncRef();
wxLogTrace(wxTRACE_FSWATCHER,
"'%s' is now watched %d times", canonical, count);
}
return true;
}
bool wxFileSystemWatcherBase::Remove(const wxFileName& path)
@@ -132,12 +143,17 @@ bool wxFileSystemWatcherBase::Remove(const wxFileName& path)
wxCHECK_MSG(it != m_watches.end(), false,
wxString::Format("Path '%s' is not watched", canonical));
// remove from watch-list
wxFSWatchInfo watch = it->second;
m_watches.erase(it);
// Decrement the watch's refcount and remove from watch-list if 0
bool ret = true;
wxFSWatchInfo& watch = it->second;
if ( !watch.DecRef() )
{
// remove in a platform specific way
ret = m_service->Remove(watch);
// remove in a platform specific way
return m_service->Remove(watch);
m_watches.erase(it);
}
return ret;
}
bool wxFileSystemWatcherBase::AddTree(const wxFileName& path, int events,

26
tests/fswatcher/fswatchertest.cpp
View File

@@ -653,6 +653,9 @@ void FileSystemWatcherTestCase::TestTrees()
void GrowTree(wxFileName dir)
{
CPPUNIT_ASSERT(dir.Mkdir());
// Now add a subdir with an easy name to remember in WatchTree()
dir.AppendDir("child");
CPPUNIT_ASSERT(dir.Mkdir());
// Create a branch of 5 numbered subdirs, each containing 3
// numbered files
@@ -711,7 +714,7 @@ void FileSystemWatcherTestCase::TestTrees()
// When there's no file mask, wxMSW sets a single watch
// on the trunk which is implemented recursively.
// wxGTK always sets an additional watch for each file/subdir
treeitems += (subdirs*files) + subdirs;
treeitems += (subdirs*files) + subdirs + 1; // +1 for 'child'
#endif // __WINDOWS__
// Store the initial count; there may already be some watches
@@ -726,6 +729,27 @@ void FileSystemWatcherTestCase::TestTrees()
m_watcher->RemoveTree(dir);
CPPUNIT_ASSERT_EQUAL(initial, m_watcher->GetWatchedPathsCount());
// Now test the refcount mechanism by watching items more than once
wxFileName child(dir);
child.AppendDir("child");
m_watcher->AddTree(child);
// Check some watches were added; we don't care about the number
CPPUNIT_ASSERT(initial < m_watcher->GetWatchedPathsCount());
// Now watch the whole tree and check that the count is the same
// as it was the first time, despite also adding 'child' separately
// Except that in wxMSW this isn't true: each watch will be a
// single, recursive dir; so fudge the count
size_t fudge = 0;
#ifdef __WINDOWS__
fudge = 1;
#endif // __WINDOWS__
m_watcher->AddTree(dir);
CPPUNIT_ASSERT_EQUAL(plustree + fudge, m_watcher->GetWatchedPathsCount());
m_watcher->RemoveTree(child);
CPPUNIT_ASSERT(initial < m_watcher->GetWatchedPathsCount());
m_watcher->RemoveTree(dir);
CPPUNIT_ASSERT_EQUAL(initial, m_watcher->GetWatchedPathsCount());
}
void WatchTreeWithFilespec(const wxFileName& dir)