From 6798315327690fdbe93add15159be5b925779bfe Mon Sep 17 00:00:00 2001
From: Tao Bao <tbao@google.com>
Date: Sat, 4 Nov 2017 00:08:08 -0700
Subject: otautil: Remove the aborts in RangeSet::Parse().

We used to CHECK and abort on parsing errors. While it works fine for
the updater use case (because recovery starts updater in a forked
process and collects the process exit code), it's difficult for other
clients to use RangeSet as a library (e.g. update_verifier).

This CL switches the aborts to returning empty RangeSet instead. Callers
need to check the parsing results explicitly.

The CL also separates RangeSet::PushBack() into a function, and moves
SortedRangeSet::Clear() into RangeSet.

Test: recovery_unit_test
Test: Sideload an OTA package with the new updater on angler.
Test: Sideload an OTA package with injected range string errors. The
      updater aborts from the explicit checks.
Change-Id: If2b7f6f41dc93af917a21c7877a83e98dc3fd016
---
 otautil/include/otautil/rangeset.h | 42 ++++++++++++++++++++++++++++----------
 1 file changed, 31 insertions(+), 11 deletions(-)

(limited to 'otautil/include')

diff --git a/otautil/include/otautil/rangeset.h b/otautil/include/otautil/rangeset.h
index c4234d181..af8ae2dee 100644
--- a/otautil/include/otautil/rangeset.h
+++ b/otautil/include/otautil/rangeset.h
@@ -30,28 +30,35 @@ class RangeSet {
 
   explicit RangeSet(std::vector<Range>&& pairs);
 
+  // Parses the given string into a RangeSet. Returns the parsed RangeSet, or an empty RangeSet on
+  // errors.
   static RangeSet Parse(const std::string& range_text);
 
+  // Appends the given Range to the current RangeSet.
+  bool PushBack(Range range);
+
+  // Clears all the ranges from the RangeSet.
+  void Clear();
+
   std::string ToString() const;
 
-  // Get the block number for the i-th (starting from 0) block in the RangeSet.
+  // Gets the block number for the i-th (starting from 0) block in the RangeSet.
   size_t GetBlockNumber(size_t idx) const;
 
-  // RangeSet has half-closed half-open bounds. For example, "3,5" contains blocks 3 and 4. So "3,5"
-  // and "5,7" are not overlapped.
+  // Returns whether the current RangeSet overlaps with other. RangeSet has half-closed half-open
+  // bounds. For example, "3,5" contains blocks 3 and 4. So "3,5" and "5,7" are not overlapped.
   bool Overlaps(const RangeSet& other) const;
 
-  // size() gives the number of Range's in this RangeSet.
+  // Returns the number of Range's in this RangeSet.
   size_t size() const {
     return ranges_.size();
   }
 
-  // blocks() gives the number of all blocks in this RangeSet.
+  // Returns the total number of blocks in this RangeSet.
   size_t blocks() const {
     return blocks_;
   }
 
-  // We provide const iterators only.
   std::vector<Range>::const_iterator cbegin() const {
     return ranges_.cbegin();
   }
@@ -60,13 +67,20 @@ class RangeSet {
     return ranges_.cend();
   }
 
-  // Need to provide begin()/end() since range-based loop expects begin()/end().
+  std::vector<Range>::iterator begin() {
+    return ranges_.begin();
+  }
+
+  std::vector<Range>::iterator end() {
+    return ranges_.end();
+  }
+
   std::vector<Range>::const_iterator begin() const {
-    return ranges_.cbegin();
+    return ranges_.begin();
   }
 
   std::vector<Range>::const_iterator end() const {
-    return ranges_.cend();
+    return ranges_.end();
   }
 
   // Reverse const iterators for MoveRange().
@@ -78,6 +92,11 @@ class RangeSet {
     return ranges_.crend();
   }
 
+  // Returns whether the RangeSet is valid (i.e. non-empty).
+  explicit operator bool() const {
+    return !ranges_.empty();
+  }
+
   const Range& operator[](size_t i) const {
     return ranges_[i];
   }
@@ -109,6 +128,9 @@ class RangeSet {
 // every block in the original source.
 class SortedRangeSet : public RangeSet {
  public:
+  // The block size when working with offset and file length.
+  static constexpr size_t kBlockSize = 4096;
+
   SortedRangeSet() {}
 
   // Ranges in the the set should be mutually exclusive; and they're sorted by the start block.
@@ -122,8 +144,6 @@ class SortedRangeSet : public RangeSet {
   // Compute the block range the file occupies, and insert that range.
   void Insert(size_t start, size_t len);
 
-  void Clear();
-
   using RangeSet::Overlaps;
 
   bool Overlaps(size_t start, size_t len) const;
-- 
cgit v1.2.3