Squashed 'src/leveldb/' changes from 20ca81f..a31c8aa

a31c8aa Add NewAppendableFile for win32 environment
1913d71 Merge upstream LevelDB 1.19
3080a45 Increase leveldb version to 1.19.
fa6dc01 A zippy change broke test assumptions about the size of compressed output. Fix the tests by allowing more slop in zippy's behavior. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=123432472
06a191b fix problems in LevelDB's caching code
a7bff69 Fix LevelDB build when asserts are enabled in release builds. (#367)
ea992b4 Change std::uint64_t to uint64_t (#354)
e84b5bd This CL fixes a bug encountered when reading records from leveldb files that have been split, as in a [] input task split.
3211343 Deleted redundant null ptr check prior to delete.
7306ef8 Merge pull request #348 from randomascii/master
6b18316 Fix signed/unsigned mismatch on VC++ builds
adbe3eb Putting build artifacts in subdirectory.
2d0320a Merge pull request #329 from ralphtheninja/travis-badge
dd1c3c3 add travis build badge
43fcf23 Merge pull request #328 from cmumford/master
9fcae61 Added a Travis CI build file.
dac40d2 Merge pull request #284 from ideawu/master
8ec241a Merge pull request #317 from falvojr/patch-1
5d36bed Merge pull request #272 from vapier/master
4753c9b Added a contributors section to README.md
e2446d0 Merge pull request #275 from paulirish/patch-1
706b7f8 Resolve race when getting approximate-memory-usage property
3c9ff3c Only compiling TrimSpace on linux.
f8d205c Including atomic_pointer.h in port_posix
889de31 Let LevelDB use xcrun to determine Xcode.app path instead of using a hardcoded path.
528c2bc Add "approximate-memory-usage" property to leveldb::DB::GetProperty
359b6bc Add leveldb::Cache::Prune
50e77a8 Fix size_t/int comparison/conversion issues in leveldb.
5208e79 Added leveldb::Status::IsInvalidArgument() method.
ce45404 Suppress error reporting after seeking but before a valid First or Full record is encountered.
b9afa1f include <assert> -> <cassert>
edf2939 Update README.md
65190ac Will not reuse manifest if reuse_logs options is false.
ac1d69d LevelDB now attempts to reuse the preceding MANIFEST and log file when re-opened.
76bba13 fix indent
8fcceb2 log compaction output file's level along with number
0e0f074 documentation. improved link
c85addc readme: improved documentation link
ceff6f1 Fix Android/MIPS build.
77948e7 Add benchmark that measures cost of repeatedly opening the database.
34ad72e Move header guard below copyright banner.
a75d435 Clean up layering of storage/leveldb/...
b234f65 Added a new fault injection test.
c4c38f9 Add arm64 support to leveldb.
cea9b10 Fixed incorrect comment wording for Iterator::Seek.
c00c569 Deleted old README file.

git-subtree-dir: src/leveldb
git-subtree-split: a31c8aa408d5594830f7cb20ead1ef1dff51b79e

6 files changed, 45 insertions, 2 deletions

diff --git a/include/leveldb/cache.h b/include/leveldb/cache.h
index 1a201e5e0a..6819d5bc49 100644
--- a/include/leveldb/cache.h
+++ b/include/leveldb/cache.h
@@ -81,6 +81,17 @@ class Cache {
   // its cache keys.
   virtual uint64_t NewId() = 0;
 
+  // Remove all cache entries that are not actively in use.  Memory-constrained
+  // applications may wish to call this method to reduce memory usage.
+  // Default implementation of Prune() does nothing.  Subclasses are strongly
+  // encouraged to override the default implementation.  A future release of
+  // leveldb may change Prune() to a pure abstract method.
+  virtual void Prune() {}
+
+  // Return an estimate of the combined charges of all elements stored in the
+  // cache.
+  virtual size_t TotalCharge() const = 0;
+
  private:
   void LRU_Remove(Handle* e);
   void LRU_Append(Handle* e);
diff --git a/include/leveldb/db.h b/include/leveldb/db.h
index 4c169bf22e..9752cbad51 100644
--- a/include/leveldb/db.h
+++ b/include/leveldb/db.h
@@ -14,7 +14,7 @@ namespace leveldb {
 
 // Update Makefile if you change these
 static const int kMajorVersion = 1;
-static const int kMinorVersion = 18;
+static const int kMinorVersion = 19;
 
 struct Options;
 struct ReadOptions;
@@ -115,6 +115,8 @@ class DB {
   //     about the internal operation of the DB.
   //  "leveldb.sstables" - returns a multi-line string that describes all
   //     of the sstables that make up the db contents.
+  //  "leveldb.approximate-memory-usage" - returns the approximate number of
+  //     bytes of memory in use by the DB.
   virtual bool GetProperty(const Slice& property, std::string* value) = 0;
 
   // For each i in [0,n-1], store in "sizes[i]", the approximate
diff --git a/include/leveldb/env.h b/include/leveldb/env.h
index f709514da6..99b6c21414 100644
--- a/include/leveldb/env.h
+++ b/include/leveldb/env.h
@@ -69,6 +69,21 @@ class Env {
   virtual Status NewWritableFile(const std::string& fname,
                                  WritableFile** result) = 0;
 
+  // Create an object that either appends to an existing file, or
+  // writes to a new file (if the file does not exist to begin with).
+  // On success, stores a pointer to the new file in *result and
+  // returns OK.  On failure stores NULL in *result and returns
+  // non-OK.
+  //
+  // The returned file will only be accessed by one thread at a time.
+  //
+  // May return an IsNotSupportedError error if this Env does
+  // not allow appending to an existing file.  Users of Env (including
+  // the leveldb implementation) must be prepared to deal with
+  // an Env that does not support appending.
+  virtual Status NewAppendableFile(const std::string& fname,
+                                   WritableFile** result);
+
   // Returns true iff the named file exists.
   virtual bool FileExists(const std::string& fname) = 0;
 
@@ -289,6 +304,9 @@ class EnvWrapper : public Env {
   Status NewWritableFile(const std::string& f, WritableFile** r) {
     return target_->NewWritableFile(f, r);
   }
+  Status NewAppendableFile(const std::string& f, WritableFile** r) {
+    return target_->NewAppendableFile(f, r);
+  }
   bool FileExists(const std::string& f) { return target_->FileExists(f); }
   Status GetChildren(const std::string& dir, std::vector<std::string>* r) {
     return target_->GetChildren(dir, r);
diff --git a/include/leveldb/iterator.h b/include/leveldb/iterator.h
index 76aced04bd..da631ed9d8 100644
--- a/include/leveldb/iterator.h
+++ b/include/leveldb/iterator.h
@@ -37,7 +37,7 @@ class Iterator {
   // Valid() after this call iff the source is not empty.
   virtual void SeekToLast() = 0;
 
-  // Position at the first key in the source that at or past target
+  // Position at the first key in the source that is at or past target.
   // The iterator is Valid() after this call iff the source contains
   // an entry that comes at or past target.
   virtual void Seek(const Slice& target) = 0;
diff --git a/include/leveldb/options.h b/include/leveldb/options.h
index 7c9b973454..83a1ef39a4 100644
--- a/include/leveldb/options.h
+++ b/include/leveldb/options.h
@@ -128,6 +128,12 @@ struct Options {
   // efficiently detect that and will switch to uncompressed mode.
   CompressionType compression;
 
+  // EXPERIMENTAL: If true, append to existing MANIFEST and log files
+  // when a database is opened.  This can significantly speed up open.
+  //
+  // Default: currently false, but may become true later.
+  bool reuse_logs;
+
   // If non-NULL, use the specified filter policy to reduce disk reads.
   // Many applications will benefit from passing the result of
   // NewBloomFilterPolicy() here.
diff --git a/include/leveldb/status.h b/include/leveldb/status.h
index 11dbd4b47e..d9575f9753 100644
--- a/include/leveldb/status.h
+++ b/include/leveldb/status.h
@@ -60,6 +60,12 @@ class Status {
   // Returns true iff the status indicates an IOError.
   bool IsIOError() const { return code() == kIOError; }
 
+  // Returns true iff the status indicates a NotSupportedError.
+  bool IsNotSupportedError() const { return code() == kNotSupported; }
+
+  // Returns true iff the status indicates an InvalidArgument.
+  bool IsInvalidArgument() const { return code() == kInvalidArgument; }
+
   // Return a string representation of this status suitable for printing.
   // Returns the string "OK" for success.
   std::string ToString() const;