Support filters for ax_dump_tree_output

The ax_dump_tree output puts out a lot of information, which can be too
noisy to efficiently read. This supports property filtering as follows:

ax_dump_tree --filters=[FILTERS_TEXT_FILE]

The filters file can have @ALLOW, @ALLOW-EMPTY and @DENY rules, similar
to the dump accessibility tree browsertests. It is not necessary to have
a platform prefix (e.g. @WIN- or @MAC-). The role of the object cannot
be filtered, but any other properties can. If no filters are provided
then all properties are shown.

Example, to filter out everything except role, name and value, use:
@ALLOW:name=*
@ALLOW:value=*

Put each filter on a separate line. For more info on writing rules, see
https://cs.chromium.org/chromium/src/content/test/data/accessibility/readme.md

Bug: 771747
Change-Id: If15a5c6f6baf6a1827749dae16825242a0913913
Reviewed-on: https://chromium-review.googlesource.com/725879
Commit-Queue: Aaron Leventhal <aleventhal@chromium.org>
Reviewed-by: Nektarios Paisios <nektar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#510171}

content/browser/accessibility/accessibility_tree_formatter_win.cc

@@ -43,7 +43,6 @@ BOOL CALLBACK EnumWindowsProcPid(HWND hwnd, LPARAM lParam) {
   HwndWithProcId* hwnd_with_proc_id = (HwndWithProcId*)lParam;
   if (process_id == static_cast<DWORD>(hwnd_with_proc_id->pid)) {
     hwnd_with_proc_id->hwnd = hwnd;
-    ;
     return FALSE;
   }
   return TRUE;
@@ -54,6 +53,7 @@ HWND GetHwndForProcess(base::ProcessId pid) {
   EnumWindows(&EnumWindowsProcPid, (LPARAM)&hwnd_with_proc_id);
   return hwnd_with_proc_id.hwnd;
 }
+
 }  // namespace
 
 namespace content {

tools/accessibility/inspect/ax_dump_tree.cc

@@ -11,6 +11,7 @@
 
 char kPidSwitch[] = "pid";
 char kWindowSwitch[] = "window";
+char kFiltersSwitch[] = "filters";
 
 // Convert from string to int, whether in 0x hex format or decimal format.
 bool StringToInt(std::string str, int* result) {
@@ -26,6 +27,11 @@ int main(int argc, char** argv) {
   base::AtExitManager at_exit_manager;
 
   base::CommandLine::Init(argc, argv);
+
+  base::string16 filters_path = base::ASCIIToUTF16(
+      base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
+          kFiltersSwitch));
+
   std::string window_str =
       base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
           kWindowSwitch);
@@ -35,7 +41,7 @@ int main(int argc, char** argv) {
       gfx::AcceleratedWidget widget(
           reinterpret_cast<gfx::AcceleratedWidget>(window));
       std::unique_ptr<content::AXTreeServer> server(
-          new content::AXTreeServer(widget));
+          new content::AXTreeServer(widget, filters_path));
       return 0;
     }
   }
@@ -46,7 +52,7 @@ int main(int argc, char** argv) {
     if (StringToInt(pid_str, &pid)) {
       base::ProcessId process_id = static_cast<base::ProcessId>(pid);
       std::unique_ptr<content::AXTreeServer> server(
-          new content::AXTreeServer(process_id));
+          new content::AXTreeServer(process_id, filters_path));
     }
   }
   return 0;

tools/accessibility/inspect/ax_tree_server.cc

@@ -9,14 +9,20 @@
 
 #include "base/at_exit.h"
 #include "base/bind.h"
-#include "base/command_line.h"
+#include "base/files/file_util.h"
+#include "base/path_service.h"
 #include "base/run_loop.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 
 namespace content {
 
-AXTreeServer::AXTreeServer(base::ProcessId pid) {
+constexpr char kAllowOptEmptyStr[] = "@ALLOW-EMPTY:";
+constexpr char kAllowOptStr[] = "@ALLOW:";
+constexpr char kDenyOptStr[] = "@DENY:";
+
+AXTreeServer::AXTreeServer(base::ProcessId pid, base::string16& filters_path) {
   std::unique_ptr<AccessibilityTreeFormatter> formatter(
       AccessibilityTreeFormatter::Create());
 
@@ -30,10 +36,11 @@ AXTreeServer::AXTreeServer(base::ProcessId pid) {
     return;
   }
 
-  Format(*formatter, *dict);
+  Format(*formatter, *dict, filters_path);
 }
 
-AXTreeServer::AXTreeServer(gfx::AcceleratedWidget widget) {
+AXTreeServer::AXTreeServer(gfx::AcceleratedWidget widget,
+                           base::string16& filters_path) {
   std::unique_ptr<AccessibilityTreeFormatter> formatter(
       AccessibilityTreeFormatter::Create());
 
@@ -46,15 +53,54 @@ AXTreeServer::AXTreeServer(gfx::AcceleratedWidget widget) {
     return;
   }
 
-  Format(*formatter, *dict);
+  Format(*formatter, *dict, filters_path);
+}
+
+std::vector<AccessibilityTreeFormatter::Filter> GetFilters(
+    const base::string16& filters_path) {
+  std::vector<AccessibilityTreeFormatter::Filter> filters;
+  if (!filters_path.empty()) {
+    std::string raw_filters_text;
+    base::ScopedAllowBlockingForTesting allow_io_for_test_setup;
+    if (base::ReadFileToString(base::FilePath(filters_path),
+                               &raw_filters_text)) {
+      for (const std::string& line :
+           base::SplitString(raw_filters_text, "\n", base::TRIM_WHITESPACE,
+                             base::SPLIT_WANT_ALL)) {
+        if (base::StartsWith(line, kAllowOptEmptyStr,
+                             base::CompareCase::SENSITIVE)) {
+          filters.push_back(AccessibilityTreeFormatter::Filter(
+              base::UTF8ToUTF16(line.substr(strlen(kAllowOptEmptyStr))),
+              AccessibilityTreeFormatter::Filter::ALLOW_EMPTY));
+        } else if (base::StartsWith(line, kAllowOptStr,
+                                    base::CompareCase::SENSITIVE)) {
+          filters.push_back(AccessibilityTreeFormatter::Filter(
+              base::UTF8ToUTF16(line.substr(strlen(kAllowOptStr))),
+              AccessibilityTreeFormatter::Filter::ALLOW));
+        } else if (base::StartsWith(line, kDenyOptStr,
+                                    base::CompareCase::SENSITIVE)) {
+          filters.push_back(AccessibilityTreeFormatter::Filter(
+              base::UTF8ToUTF16(line.substr(strlen(kDenyOptStr))),
+              AccessibilityTreeFormatter::Filter::DENY));
+        }
+      }
+    }
+  }
+  if (filters.empty()) {
+    filters = {AccessibilityTreeFormatter::Filter(
+        base::ASCIIToUTF16("*"), AccessibilityTreeFormatter::Filter::ALLOW)};
+  }
+
+  return filters;
 }
 
 void AXTreeServer::Format(AccessibilityTreeFormatter& formatter,
-                          base::DictionaryValue& dict) {
+                          base::DictionaryValue& dict,
+                          base::string16& filters_path) {
+  std::vector<AccessibilityTreeFormatter::Filter> filters =
+      GetFilters(filters_path);
+
   // Set filters.
-  std::vector<AccessibilityTreeFormatter::Filter> filters;
-  filters.push_back(AccessibilityTreeFormatter::Filter(
-      base::ASCIIToUTF16("*"), AccessibilityTreeFormatter::Filter::ALLOW));
   formatter.SetFilters(filters);
 
   // Format accessibility tree as text.

tools/accessibility/inspect/ax_tree_server.h

@@ -13,14 +13,15 @@ namespace content {
 
 class AXTreeServer {
  public:
-  explicit AXTreeServer(base::ProcessId pid);
-  explicit AXTreeServer(gfx::AcceleratedWidget widget);
+  AXTreeServer(base::ProcessId pid, base::string16& filters_path);
+  AXTreeServer(gfx::AcceleratedWidget widget, base::string16& filters_path);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AXTreeServer);
 
   void Format(AccessibilityTreeFormatter& formatter,
-              base::DictionaryValue& dict);
+              base::DictionaryValue& dict,
+              base::string16& filters_path);
 };
 
 }  // namespace content