lshal: pretty print table.

Table column length is not hardcoded, but computed
from length of each cell.

Without --neat, table column length varies for each
table.

As an effect, --neat does not emit debug info. Update
warning messages to reflect this.

Test: lshal
Test: lshal_test
Test: lshal --neat

Bug: 35389839

Change-Id: Id1d626a10ba58e20d2799854432dba74cfeaae6f
diff --git a/cmds/lshal/TextTable.h b/cmds/lshal/TextTable.h
new file mode 100644
index 0000000..4636f15
--- /dev/null
+++ b/cmds/lshal/TextTable.h
@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FRAMEWORK_NATIVE_CMDS_LSHAL_TEXT_TABLE_H_
+#define FRAMEWORK_NATIVE_CMDS_LSHAL_TEXT_TABLE_H_
+
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include "TableEntry.h"
+
+namespace android {
+namespace lshal {
+
+// An element in TextTable. This is either an actual row (an array of cells
+// in this row), or a string of explanatory text.
+// To see if this is an actual row, test fields().empty().
+class TextTableRow {
+public:
+    // An empty line.
+    TextTableRow() {}
+
+    // A row of cells.
+    TextTableRow(std::vector<std::string>&& v) : mFields(std::move(v)) {}
+
+    // A single comment string.
+    TextTableRow(std::string&& s) : mLine(std::move(s)) {}
+    TextTableRow(const std::string& s) : mLine(s) {}
+
+    // Whether this row is an actual row of cells.
+    bool isRow() const { return !fields().empty(); }
+
+    // Get all cells.
+    const std::vector<std::string>& fields() const { return mFields; }
+
+    // Get the single comment string.
+    const std::string& line() const { return mLine; }
+
+private:
+    std::vector<std::string> mFields;
+    std::string mLine;
+};
+
+// A TextTable is a 2D array of strings.
+class TextTable {
+public:
+
+    // Add a TextTableRow.
+    void add() { mTable.emplace_back(); }
+    void add(std::vector<std::string>&& v) {
+        computeWidth(v);
+        mTable.emplace_back(std::move(v));
+    }
+    void add(const std::string& s) { mTable.emplace_back(s); }
+    void add(std::string&& s) { mTable.emplace_back(std::move(s)); }
+
+    // Prints the table to out, with column widths adjusted appropriately according
+    // to the content.
+    void dump(std::ostream& out) const;
+
+private:
+    void computeWidth(const std::vector<std::string>& v);
+    std::vector<size_t> mWidths;
+    std::vector<TextTableRow> mTable;
+};
+
+} // namespace lshal
+} // namespace android
+
+#endif // FRAMEWORK_NATIVE_CMDS_LSHAL_TEXT_TABLE_H_