Add SkSpan support to the Skia LLDB visualizer.

Change-Id: Ib974e7c1003ca674cbcd67e62b6c2c328c1c2266
Bug: skia:11103
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/346639
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Adlai Holler <adlai@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Adlai Holler <adlai@google.com>

platform_tools/debugging/lldb/skia.py

@@ -46,7 +46,9 @@ class SkTArray_SynthProvider:
     def num_children(self):
         try:
             count = self.fCount.GetValueAsSigned(0)
-            return count if count >= 0 else 0
+            count = max(count, 0)
+            count = min(count, 10000)
+            return count
         except:
             return 0
 
@@ -90,7 +92,9 @@ class SkAutoTArray_SynthProvider:
     def num_children(self):
         try:
             count = self.fCount.GetValueAsSigned(0)
-            return count if count >= 0 else 0
+            count = max(count, 0)
+            count = min(count, 10000)
+            return count
         except:
             return 0
 
@@ -129,6 +133,53 @@ class SkAutoTArray_SynthProvider:
         return True
 
 
+class SkSpan_SynthProvider:
+
+    def __init__(self, valobj, dict):
+        self.valobj = valobj
+
+    def num_children(self):
+        try:
+            count = self.fSize.GetValueAsSigned(0)
+            count = max(count, 0)
+            count = min(count, 10000)
+            return count
+        except:
+            return 0
+
+    def get_child_index(self, name):
+        try:
+            return int(name.lstrip('[').rstrip(']'))
+        except:
+            return -1
+
+    def get_child_at_index(self, index):
+        if index < 0:
+            return None
+        if index >= self.num_children():
+            return None
+
+        try:
+            offset = index * self.dataSize
+            return self.fPtr.CreateChildAtOffset('[' + str(index) + ']',
+                                                 offset, self.dataType)
+        except:
+            return None
+
+    def update(self):
+        try:
+            self.fPtr = self.valobj.GetChildMemberWithName('fPtr')
+            self.fSize = self.valobj.GetChildMemberWithName('fSize')
+            self.dataType = self.fPtr.GetType().GetPointeeType()
+            self.dataSize = self.dataType.GetByteSize()
+        except:
+            pass
+
+    def has_children(self):
+        return True
+
+
+
 class sk_sp_SynthProvider:
 
     def __init__(self, valobj, dict):
@@ -162,6 +213,8 @@ def __lldb_init_module(debugger, dict):
         'type summary add --summary-string "fPtr = ${var.fPtr}" -x "^sk_sp<.+>$" -w skia')
     debugger.HandleCommand(
         'type synthetic add -l skia.SkTArray_SynthProvider -x "^SkS?TArray<.+>$" -w skia')
+    debugger.HandleCommand(
+        'type synthetic add -l skia.SkSpan_SynthProvider -x "^SkSpan<.+>$" -w skia')
     debugger.HandleCommand(
         'type summary add --summary-string "size=${svar%#}" -e -x "^SkS?TArray<.+>$" -w skia')
     debugger.HandleCommand(